Search Results

Search found 39386 results on 1576 pages for 'public ip'.

Page 175/1576 | < Previous Page | 171 172 173 174 175 176 177 178 179 180 181 182  | Next Page >

• Diving into OpenStack Network Architecture - Part 1

  - by Ronen Kofman

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} rkofman Normal rkofman 83 3045 2014-05-23T21:11:00Z 2014-05-27T06:58:00Z 3 1883 10739 Oracle Corporation 89 25 12597 12.00 140 Clean Clean false false false false EN-US X-NONE HE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi; mso-bidi-language:AR-SA;} Before we begin OpenStack networking has very powerful capabilities but at the same time it is quite complicated. In this blog series we will review an existing OpenStack setup using the Oracle OpenStack Tech Preview and explain the different network components through use cases and examples. The goal is to show how the different pieces come together and provide a bigger picture view of the network architecture in OpenStack. This can be very helpful to users making their first steps in OpenStack or anyone wishes to understand how networking works in this environment.  We will go through the basics first and build the examples as we go. According to the recent Icehouse user survey and the one before it, Neutron with Open vSwitch plug-in is the most widely used network setup both in production and in POCs (in terms of number of customers) and so in this blog series we will analyze this specific OpenStack networking setup. As we know there are many options to setup OpenStack networking and while Neturon + Open vSwitch is the most popular setup there is no claim that it is either best or the most efficient option. Neutron + Open vSwitch is an example, one which provides a good starting point for anyone interested in understanding OpenStack networking. Even if you are using different kind of network setup such as different Neutron plug-in or even not using Neutron at all this will still be a good starting point to understand the network architecture in OpenStack. The setup we are using for the examples is the one used in the Oracle OpenStack Tech Preview. Installing it is simple and it would be helpful to have it as reference. In this setup we use eth2 on all servers for VM network, all VM traffic will be flowing through this interface.The Oracle OpenStack Tech Preview is using VLANs for L2 isolation to provide tenant and network isolation. The following diagram shows how we have configured our deployment: This first post is a bit long and will focus on some basic concepts in OpenStack networking. The components we will be discussing are Open vSwitch, network namespaces, Linux bridge and veth pairs. Note that this is not meant to be a comprehensive review of these components, it is meant to describe the component as much as needed to understand OpenStack network architecture. All the components described here can be further explored using other resources. Open vSwitch (OVS) In the Oracle OpenStack Tech Preview OVS is used to connect virtual machines to the physical port (in our case eth2) as shown in the deployment diagram. OVS contains bridges and ports, the OVS bridges are different from the Linux bridge (controlled by the brctl command) which are also used in this setup. To get started let’s view the OVS structure, use the following command: # ovs-vsctl show 7ec51567-ab42-49e8-906d-b854309c9edf     Bridge br-int         Port br-int             Interface br-int type: internal         Port "int-br-eth2"             Interface "int-br-eth2"     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2" type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2" ovs_version: "1.11.0" We see a standard post deployment OVS on a compute node with two bridges and several ports hanging off of each of them. The example above is a compute node without any VMs, we can see that the physical port eth2 is connected to a bridge called “br-eth2”. We also see two ports "int-br-eth2" and "phy-br-eth2" which are actually a veth pair and form virtual wire between the two bridges, veth pairs are discussed later in this post. When a virtual machine is created a port is created on one the br-int bridge and this port is eventually connected to the virtual machine (we will discuss the exact connectivity later in the series). Here is how OVS looks after a VM was launched: # ovs-vsctl show efd98c87-dc62-422d-8f73-a68c2a14e73d     Bridge br-int         Port "int-br-eth2"             Interface "int-br-eth2"         Port br-int             Interface br-int type: internal         Port "qvocb64ea96-9f" tag: 1             Interface "qvocb64ea96-9f"     Bridge "br-eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"         Port "br-eth2"             Interface "br-eth2" type: internal         Port "eth2"             Interface "eth2" ovs_version: "1.11.0" Bridge "br-int" now has a new port "qvocb64ea96-9f" which connects to the VM and tagged with VLAN 1. Every VM which will be launched will add a port on the “br-int” bridge for every network interface the VM has. Another useful command on OVS is dump-flows for example: # ovs-ofctl dump-flows br-int NXST_FLOW reply (xid=0x4): cookie=0x0, duration=735.544s, table=0, n_packets=70, n_bytes=9976, idle_age=17, priority=3,in_port=1,dl_vlan=1000 actions=mod_vlan_vid:1,NORMAL cookie=0x0, duration=76679.786s, table=0, n_packets=0, n_bytes=0, idle_age=65534, hard_age=65534, priority=2,in_port=1 actions=drop cookie=0x0, duration=76681.36s, table=0, n_packets=68, n_bytes=7950, idle_age=17, hard_age=65534, priority=1 actions=NORMAL As we see the port which is connected to the VM has the VLAN tag 1. However the port on the VM network (eth2) will be using tag 1000. OVS is modifying the vlan as the packet flow from the VM to the physical interface. In OpenStack the Open vSwitch agent takes care of programming the flows in Open vSwitch so the users do not have to deal with this at all. If you wish to learn more about how to program the Open vSwitch you can read more about it at http://openvswitch.org looking at the documentation describing the ovs-ofctl command. Network Namespaces (netns) Network namespaces is a very cool Linux feature can be used for many purposes and is heavily used in OpenStack networking. Network namespaces are isolated containers which can hold a network configuration and is not seen from outside of the namespace. A network namespace can be used to encapsulate specific network functionality or provide a network service in isolation as well as simply help to organize a complicated network setup. Using the Oracle OpenStack Tech Preview we are using the latest Unbreakable Enterprise Kernel R3 (UEK3), this kernel provides a complete support for netns. Let's see how namespaces work through couple of examples to control network namespaces we use the ip netns command: Defining a new namespace: # ip netns add my-ns # ip netns list my-ns As mentioned the namespace is an isolated container, we can perform all the normal actions in the namespace context using the exec command for example running the ifconfig command: # ip netns exec my-ns ifconfig -a lo        Link encap:Local Loopback           LOOPBACK  MTU:16436 Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) We can run every command in the namespace context, this is especially useful for debug using tcpdump command, we can ping or ssh or define iptables all within the namespace. Connecting the namespace to the outside world: There are various ways to connect into a namespaces and between namespaces we will focus on how this is done in OpenStack. OpenStack uses a combination of Open vSwitch and network namespaces. OVS defines the interfaces and then we can add those interfaces to namespace. So first let's add a bridge to OVS: # ovs-vsctl add-br my-bridge Now let's add a port on the OVS and make it internal: # ovs-vsctl add-port my-bridge my-port # ovs-vsctl set Interface my-port type=internal And let's connect it into the namespace: # ip link set my-port netns my-ns Looking inside the namespace: # ip netns exec my-ns ifconfig -a lo        Link encap:Local Loopback           LOOPBACK  MTU:65536 Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) my-port   Link encap:Ethernet HWaddr 22:04:45:E2:85:21           BROADCAST  MTU:1500 Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) Now we can add more ports to the OVS bridge and connect it to other namespaces or other device like physical interfaces. Neutron is using network namespaces to implement network services such as DCHP, routing, gateway, firewall, load balance and more. In the next post we will go into this in further details. Linux Bridge and veth pairs Linux bridge is used to connect the port from OVS to the VM. Every port goes from the OVS bridge to a Linux bridge and from there to the VM. The reason for using regular Linux bridges is for security groups’ enforcement. Security groups are implemented using iptables and iptables can only be applied to Linux bridges and not to OVS bridges. Veth pairs are used extensively throughout the network setup in OpenStack and are also a good tool to debug a network problem. Veth pairs are simply a virtual wire and so veths always come in pairs. Typically one side of the veth pair will connect to a bridge and the other side to another bridge or simply left as a usable interface. In this example we will create some veth pairs, connect them to bridges and test connectivity. This example is using regular Linux server and not an OpenStack node: Creating a veth pair, note that we define names for both ends: # ip link add veth0 type veth peer name veth1 # ifconfig -a . . veth0     Link encap:Ethernet HWaddr 5E:2C:E6:03:D0:17           BROADCAST MULTICAST  MTU:1500 Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) veth1     Link encap:Ethernet HWaddr E6:B6:E2:6D:42:B8           BROADCAST MULTICAST  MTU:1500 Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) . . To make the example more meaningful this we will create the following setup: veth0 => veth1 => br-eth3 => eth3 ======> eth2 on another Linux server br-eth3 – a regular Linux bridge which will be connected to veth1 and eth3 eth3 – a physical interface with no IP on it, connected to a private network eth2 – a physical interface on the remote Linux box connected to the private network and configured with the IP of 50.50.50.1 Once we create the setup we will ping 50.50.50.1 (the remote IP) through veth0 to test that the connection is up: # brctl addbr br-eth3 # brctl addif br-eth3 eth3 # brctl addif br-eth3 veth1 # brctl show bridge name     bridge id               STP enabled     interfaces br-eth3         8000.00505682e7f6       no              eth3                                                         veth1 # ifconfig veth0 50.50.50.50 # ping -I veth0 50.50.50.51 PING 50.50.50.51 (50.50.50.51) from 50.50.50.50 veth0: 56(84) bytes of data. 64 bytes from 50.50.50.51: icmp_seq=1 ttl=64 time=0.454 ms 64 bytes from 50.50.50.51: icmp_seq=2 ttl=64 time=0.298 ms When the naming is not as obvious as the previous example and we don't know who are the paired veth interfaces we can use the ethtool command to figure this out. The ethtool command returns an index we can look up using ip link command, for example: # ethtool -S veth1 NIC statistics: peer_ifindex: 12 # ip link . . 12: veth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 Summary That’s all for now, we quickly reviewed OVS, network namespaces, Linux bridges and veth pairs. These components are heavily used in the OpenStack network architecture we are exploring and understanding them well will be very useful when reviewing the different use cases. In the next post we will look at how the OpenStack network is laid out connecting the virtual machines to each other and to the external world. @RonenKofman

  Read the article

• Can't figure out error in Cisco ASA log "regular translation creation failed for icmp ..."

  - by Martijn Heemels

  Every few seconds our new Cisco ASA 5505 firewall is logging errors that I can't figure out with my limited Cisco experience. Severity Date Time Syslog ID Source IP Destination IP Description 3 Mar 25 2010 17:21:14 305006 8.8.8.8 regular translation creation failed for icmp src inside:10.10.0.200 dst outside:8.8.8.8 (type 3, code 3) 3 Mar 25 2010 17:18:37 305006 8.8.4.4 regular translation creation failed for icmp src inside:10.10.0.200 dst outside:8.8.4.4 (type 3, code 3) The logged inside IP is our internal DNS resolver, and the outside IP's are Google's public DNS servers. ICMP Type 3 Code 3 means "Port Unreachable" Our "outside" interface has a fixed IP and our "inside" interface is in the 10.10.0.0/16 subnet. The 'Inspect DNS' Service Policy is enabled, with the preset DNS inspection map. Furthermore there's an ACL that allows all inbound ICMP on the "outside" interface. I've spent hours trying to figure this one out, so any and all advice is welcome!

  Read the article

• Using RIA DomainServices with ASP.NET and MVC 2

  - by Bobby Diaz

  Recently, I started working on a new ASP.NET MVC 2 project and I wanted to reuse the data access (LINQ to SQL) and business logic methods (WCF RIA Services) that had been developed for a previous project that used Silverlight for the front-end.  I figured that I would be able to instantiate the various DomainService classes from within my controller’s action methods, because after all, the code for those services didn’t look very complicated.  WRONG!  I didn’t realize at first that some of the functionality is handled automatically by the framework when the domain services are hosted as WCF services.  After some initial searching, I came across an invaluable post by Joe McBride, which described how to get RIA Service .svc files to work in an MVC 2 Web Application, and another by Brad Abrams.  Unfortunately, Brad’s solution was for an earlier preview release of RIA Services and no longer works with the version that I am running (PDC Preview). I have not tried the RC version of WCF RIA Services, so I am not sure if any of the issues I am having have been resolved, but I wanted to come up with a way to reuse the shared libraries so I wouldn’t have to write a non-RIA version that basically did the same thing.  The classes I came up with work with the scenarios I have encountered so far, but I wanted to go ahead and post the code in case someone else is having the same trouble I had.  Hopefully this will save you a few headaches! 1. Querying When I first tried to use a DomainService class to perform a query inside one of my controller’s action methods, I got an error stating that “This DomainService has not been initialized.”  To solve this issue, I created an extension method for all DomainServices that creates the required DomainServiceContext and passes it to the service’s Initialize() method.  Here is the code for the extension method; notice that I am creating a sort of mock HttpContext for those cases when the service is running outside of IIS, such as during unit testing!     public static class ServiceExtensions     {         /// <summary>         /// Initializes the domain service by creating a new <see cref="DomainServiceContext"/>         /// and calling the base DomainService.Initialize(DomainServiceContext) method.         /// </summary>         /// <typeparam name="TService">The type of the service.</typeparam>         /// <param name="service">The service.</param>         /// <returns></returns>         public static TService Initialize<TService>(this TService service)             where TService : DomainService         {             var context = CreateDomainServiceContext();             service.Initialize(context);             return service;         }           private static DomainServiceContext CreateDomainServiceContext()         {             var provider = new ServiceProvider(new HttpContextWrapper(GetHttpContext()));             return new DomainServiceContext(provider, DomainOperationType.Query);         }           private static HttpContext GetHttpContext()         {             var context = HttpContext.Current;   #if DEBUG             // create a mock HttpContext to use during unit testing...             if ( context == null )             {                 var writer = new StringWriter();                 var request = new SimpleWorkerRequest("/", "/",                     String.Empty, String.Empty, writer);                   context = new HttpContext(request)                 {                     User = new GenericPrincipal(new GenericIdentity("debug"), null)                 };             } #endif               return context;         }     }   With that in place, I can use it almost as normally as my first attempt, except with a call to Initialize():     public ActionResult Index()     {         var service = new NorthwindService().Initialize();         var customers = service.GetCustomers();           return View(customers);     } 2. Insert / Update / Delete Once I got the records showing up, I was trying to insert new records or update existing data when I ran into the next issue.  I say issue because I wasn’t getting any kind of error, which made it a little difficult to track down.  But once I realized that that the DataContext.SubmitChanges() method gets called automatically at the end of each domain service submit operation, I could start working on a way to mimic the behavior of a hosted domain service.  What I came up with, was a base class called LinqToSqlRepository<T> that basically sits between your implementation and the default LinqToSqlDomainService<T> class.     [EnableClientAccess()]     public class NorthwindService : LinqToSqlRepository<NorthwindDataContext>     {         public IQueryable<Customer> GetCustomers()         {             return this.DataContext.Customers;         }           public void InsertCustomer(Customer customer)         {             this.DataContext.Customers.InsertOnSubmit(customer);         }           public void UpdateCustomer(Customer currentCustomer)         {             this.DataContext.Customers.TryAttach(currentCustomer,                 this.ChangeSet.GetOriginal(currentCustomer));         }           public void DeleteCustomer(Customer customer)         {             this.DataContext.Customers.TryAttach(customer);             this.DataContext.Customers.DeleteOnSubmit(customer);         }     } Notice the new base class name (just change LinqToSqlDomainService to LinqToSqlRepository).  I also added a couple of DataContext (for Table<T>) extension methods called TryAttach that will check to see if the supplied entity is already attached before attempting to attach it, which would cause an error! 3. LinqToSqlRepository<T> Below is the code for the LinqToSqlRepository class.  The comments are pretty self explanatory, but be aware of the [IgnoreOperation] attributes on the generic repository methods, which ensures that they will be ignored by the code generator and not available in the Silverlight client application.     /// <summary>     /// Provides generic repository methods on top of the standard     /// <see cref="LinqToSqlDomainService&lt;TContext&gt;"/> functionality.     /// </summary>     /// <typeparam name="TContext">The type of the context.</typeparam>     public abstract class LinqToSqlRepository<TContext> : LinqToSqlDomainService<TContext>         where TContext : System.Data.Linq.DataContext, new()     {         /// <summary>         /// Retrieves an instance of an entity using it's unique identifier.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="keyValues">The key values.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual TEntity GetById<TEntity>(params object[] keyValues) where TEntity : class         {             var table = this.DataContext.GetTable<TEntity>();             var mapping = this.DataContext.Mapping.GetTable(typeof(TEntity));               var keys = mapping.RowType.IdentityMembers                 .Select((m, i) => m.Name + " = @" + i)                 .ToArray();               return table.Where(String.Join(" && ", keys), keyValues).FirstOrDefault();         }           /// <summary>         /// Creates a new query that can be executed to retrieve a collection         /// of entities from the <see cref="DataContext"/>.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <returns></returns>         [IgnoreOperation]         public virtual IQueryable<TEntity> GetEntityQuery<TEntity>() where TEntity : class         {             return this.DataContext.GetTable<TEntity>();         }           /// <summary>         /// Inserts the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Insert<TEntity>(TEntity entity) where TEntity : class         {             //var table = this.DataContext.GetTable<TEntity>();             //table.InsertOnSubmit(entity);               return this.Submit(entity, null, DomainOperation.Insert);         }           /// <summary>         /// Updates the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Update<TEntity>(TEntity entity) where TEntity : class         {             return this.Update(entity, null);         }           /// <summary>         /// Updates the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <param name="original">The original.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Update<TEntity>(TEntity entity, TEntity original)             where TEntity : class         {             if ( original == null )             {                 original = GetOriginal(entity);             }               var table = this.DataContext.GetTable<TEntity>();             table.TryAttach(entity, original);               return this.Submit(entity, original, DomainOperation.Update);         }           /// <summary>         /// Deletes the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Delete<TEntity>(TEntity entity) where TEntity : class         {             //var table = this.DataContext.GetTable<TEntity>();             //table.TryAttach(entity);             //table.DeleteOnSubmit(entity);               return this.Submit(entity, null, DomainOperation.Delete);         }           protected virtual bool Submit(Object entity, Object original, DomainOperation operation)         {             var entry = new ChangeSetEntry(0, entity, original, operation);             var changes = new ChangeSet(new ChangeSetEntry[] { entry });             return base.Submit(changes);         }           private TEntity GetOriginal<TEntity>(TEntity entity) where TEntity : class         {             var context = CreateDataContext();             var table = context.GetTable<TEntity>();             return table.FirstOrDefault(e => e == entity);         }     } 4. Conclusion So there you have it, a fully functional Repository implementation for your RIA Domain Services that can be consumed by your ASP.NET and MVC applications.  I have uploaded the source code along with unit tests and a sample web application that queries the Customers table from inside a Controller, as well as a Silverlight usage example. As always, I welcome any comments or suggestions on the approach I have taken.  If there is enough interest, I plan on contacting Colin Blair or maybe even the man himself, Brad Abrams, to see if this is something worthy of inclusion in the WCF RIA Services Contrib project.  What do you think? Enjoy!

  Read the article

• Basic Spatial Data with SQL Server and Entity Framework 5.0

  - by Rick Strahl

  In my most recent project we needed to do a bit of geo-spatial referencing. While spatial features have been in SQL Server for a while using those features inside of .NET applications hasn't been as straight forward as could be, because .NET natively doesn't support spatial types. There are workarounds for this with a few custom project like SharpMap or a hack using the Sql Server specific Geo types found in the Microsoft.SqlTypes assembly that ships with SQL server. While these approaches work for manipulating spatial data from .NET code, they didn't work with database access if you're using Entity Framework. Other ORM vendors have been rolling their own versions of spatial integration. In Entity Framework 5.0 running on .NET 4.5 the Microsoft ORM finally adds support for spatial types as well. In this post I'll describe basic geography features that deal with single location and distance calculations which is probably the most common usage scenario. SQL Server Transact-SQL Syntax for Spatial Data Before we look at how things work with Entity framework, lets take a look at how SQL Server allows you to use spatial data to get an understanding of the underlying semantics. The following SQL examples should work with SQL 2008 and forward. Let's start by creating a test table that includes a Geography field and also a pair of Long/Lat fields that demonstrate how you can work with the geography functions even if you don't have geography/geometry fields in the database. Here's the CREATE command:CREATE TABLE [dbo].[Geo]( [id] [int] IDENTITY(1,1) NOT NULL, [Location] [geography] NULL, [Long] [float] NOT NULL, [Lat] [float] NOT NULL ) Now using plain SQL you can insert data into the table using geography::STGeoFromText SQL CLR function:insert into Geo( Location , long, lat ) values ( geography::STGeomFromText ('POINT(-121.527200 45.712113)', 4326), -121.527200, 45.712113 ) insert into Geo( Location , long, lat ) values ( geography::STGeomFromText ('POINT(-121.517265 45.714240)', 4326), -121.517265, 45.714240 ) insert into Geo( Location , long, lat ) values ( geography::STGeomFromText ('POINT(-121.511536 45.714825)', 4326), -121.511536, 45.714825) The STGeomFromText function accepts a string that points to a geometric item (a point here but can also be a line or path or polygon and many others). You also need to provide an SRID (Spatial Reference System Identifier) which is an integer value that determines the rules for how geography/geometry values are calculated and returned. For mapping/distance functionality you typically want to use 4326 as this is the format used by most mapping software and geo-location libraries like Google and Bing. The spatial data in the Location field is stored in binary format which looks something like this: Once the location data is in the database you can query the data and do simple distance computations very easily. For example to calculate the distance of each of the values in the database to another spatial point is very easy to calculate. Distance calculations compare two points in space using a direct line calculation. For our example I'll compare a new point to all the points in the database. Using the Location field the SQL looks like this:-- create a source point DECLARE @s geography SET @s = geography:: STGeomFromText('POINT(-121.527200 45.712113)' , 4326); --- return the ids select ID, Location as Geo , Location .ToString() as Point , @s.STDistance( Location) as distance from Geo order by distance The code defines a new point which is the base point to compare each of the values to. You can also compare values from the database directly, but typically you'll want to match a location to another location and determine the difference for which you can use the geography::STDistance function. This query produces the following output: The STDistance function returns the straight line distance between the passed in point and the point in the database field. The result for SRID 4326 is always in meters. Notice that the first value passed was the same point so the difference is 0. The other two points are two points here in town in Hood River a little ways away - 808 and 1256 meters respectively. Notice also that you can order the result by the resulting distance, which effectively gives you results that are ordered radially out from closer to further away. This is great for searches of points of interest near a central location (YOU typically!). These geolocation functions are also available to you if you don't use the Geography/Geometry types, but plain float values. It's a little more work, as each point has to be created in the query using the string syntax, but the following code doesn't use a geography field but produces the same result as the previous query.--- using float fields select ID, geography::STGeomFromText ('POINT(' + STR (long, 15,7 ) + ' ' + Str(lat ,15, 7) + ')' , 4326), geography::STGeomFromText ('POINT(' + STR (long, 15,7 ) + ' ' + Str(lat ,15, 7) + ')' , 4326). ToString(), @s.STDistance( geography::STGeomFromText ('POINT(' + STR(long ,15, 7) + ' ' + Str(lat ,15, 7) + ')' , 4326)) as distance from geo order by distance Spatial Data in the Entity Framework Prior to Entity Framework 5.0 on .NET 4.5 consuming of the data above required using stored procedures or raw SQL commands to access the spatial data. In Entity Framework 5 however, Microsoft introduced the new DbGeometry and DbGeography types. These immutable location types provide a bunch of functionality for manipulating spatial points using geometry functions which in turn can be used to do common spatial queries like I described in the SQL syntax above. The DbGeography/DbGeometry types are immutable, meaning that you can't write to them once they've been created. They are a bit odd in that you need to use factory methods in order to instantiate them - they have no constructor() and you can't assign to properties like Latitude and Longitude. Creating a Model with Spatial Data Let's start by creating a simple Entity Framework model that includes a Location property of type DbGeography: public class GeoLocationContext : DbContext { public DbSet<GeoLocation> Locations { get; set; } } public class GeoLocation { public int Id { get; set; } public DbGeography Location { get; set; } public string Address { get; set; } } That's all there's to it. When you run this now against SQL Server, you get a Geography field for the Location property, which looks the same as the Location field in the SQL examples earlier. Adding Spatial Data to the Database Next let's add some data to the table that includes some latitude and longitude data. An easy way to find lat/long locations is to use Google Maps to pinpoint your location, then right click and click on What's Here. Click on the green marker to get the GPS coordinates. To add the actual geolocation data create an instance of the GeoLocation type and use the DbGeography.PointFromText() factory method to create a new point to assign to the Location property:[TestMethod] public void AddLocationsToDataBase() { var context = new GeoLocationContext(); // remove all context.Locations.ToList().ForEach( loc => context.Locations.Remove(loc)); context.SaveChanges(); var location = new GeoLocation() { // Create a point using native DbGeography Factory method Location = DbGeography.PointFromText( string.Format("POINT({0} {1})", -121.527200,45.712113) ,4326), Address = "301 15th Street, Hood River" }; context.Locations.Add(location); location = new GeoLocation() { Location = CreatePoint(45.714240, -121.517265), Address = "The Hatchery, Bingen" }; context.Locations.Add(location); location = new GeoLocation() { // Create a point using a helper function (lat/long) Location = CreatePoint(45.708457, -121.514432), Address = "Kaze Sushi, Hood River" }; context.Locations.Add(location); location = new GeoLocation() { Location = CreatePoint(45.722780, -120.209227), Address = "Arlington, OR" }; context.Locations.Add(location); context.SaveChanges(); } As promised, a DbGeography object has to be created with one of the static factory methods provided on the type as the Location.Longitude and Location.Latitude properties are read only. Here I'm using PointFromText() which uses a "Well Known Text" format to specify spatial data. In the first example I'm specifying to create a Point from a longitude and latitude value, using an SRID of 4326 (just like earlier in the SQL examples). You'll probably want to create a helper method to make the creation of Points easier to avoid that string format and instead just pass in a couple of double values. Here's my helper called CreatePoint that's used for all but the first point creation in the sample above:public static DbGeography CreatePoint(double latitude, double longitude) { var text = string.Format(CultureInfo.InvariantCulture.NumberFormat, "POINT({0} {1})", longitude, latitude); // 4326 is most common coordinate system used by GPS/Maps return DbGeography.PointFromText(text, 4326); } Using the helper the syntax becomes a bit cleaner, requiring only a latitude and longitude respectively. Note that my method intentionally swaps the parameters around because Latitude and Longitude is the common format I've seen with mapping libraries (especially Google Mapping/Geolocation APIs with their LatLng type). When the context is changed the data is written into the database using the SQL Geography type which looks the same as in the earlier SQL examples shown. Querying Once you have some location data in the database it's now super easy to query the data and find out the distance between locations. A common query is to ask for a number of locations that are near a fixed point - typically your current location and order it by distance. Using LINQ to Entities a query like this is easy to construct:[TestMethod] public void QueryLocationsTest() { var sourcePoint = CreatePoint(45.712113, -121.527200); var context = new GeoLocationContext(); // find any locations within 5 kilometers ordered by distance var matches = context.Locations .Where(loc => loc.Location.Distance(sourcePoint) < 5000) .OrderBy( loc=> loc.Location.Distance(sourcePoint) ) .Select( loc=> new { Address = loc.Address, Distance = loc.Location.Distance(sourcePoint) }); Assert.IsTrue(matches.Count() > 0); foreach (var location in matches) { Console.WriteLine("{0} ({1:n0} meters)", location.Address, location.Distance); } } This example produces: 301 15th Street, Hood River (0 meters)The Hatchery, Bingen (809 meters)Kaze Sushi, Hood River (1,074 meters)   The first point in the database is the same as my source point I'm comparing against so the distance is 0. The other two are within the 5 mile radius, while the Arlington location which is 65 miles or so out is not returned. The result is ordered by distance from closest to furthest away. In the code, I first create a source point that is the basis for comparison. The LINQ query then selects all locations that are within 5km of the source point using the Location.Distance() function, which takes a source point as a parameter. You can either use a pre-defined value as I'm doing here, or compare against another database DbGeography property (say when you have to points in the same database for things like routes). What's nice about this query syntax is that it's very clean and easy to read and understand. You can calculate the distance and also easily order by the distance to provide a result that shows locations from closest to furthest away which is a common scenario for any application that places a user in the context of several locations. It's now super easy to accomplish this. Meters vs. Miles As with the SQL Server functions, the Distance() method returns data in meters, so if you need to work with miles or feet you need to do some conversion. Here are a couple of helpers that might be useful (can be found in GeoUtils.cs of the sample project):/// <summary> /// Convert meters to miles /// </summary> /// <param name="meters"></param> /// <returns></returns> public static double MetersToMiles(double? meters) { if (meters == null) return 0F; return meters.Value * 0.000621371192; } /// <summary> /// Convert miles to meters /// </summary> /// <param name="miles"></param> /// <returns></returns> public static double MilesToMeters(double? miles) { if (miles == null) return 0; return miles.Value * 1609.344; } Using these two helpers you can query on miles like this:[TestMethod] public void QueryLocationsMilesTest() { var sourcePoint = CreatePoint(45.712113, -121.527200); var context = new GeoLocationContext(); // find any locations within 5 miles ordered by distance var fiveMiles = GeoUtils.MilesToMeters(5); var matches = context.Locations .Where(loc => loc.Location.Distance(sourcePoint) <= fiveMiles) .OrderBy(loc => loc.Location.Distance(sourcePoint)) .Select(loc => new { Address = loc.Address, Distance = loc.Location.Distance(sourcePoint) }); Assert.IsTrue(matches.Count() > 0); foreach (var location in matches) { Console.WriteLine("{0} ({1:n1} miles)", location.Address, GeoUtils.MetersToMiles(location.Distance)); } } which produces: 301 15th Street, Hood River (0.0 miles)The Hatchery, Bingen (0.5 miles)Kaze Sushi, Hood River (0.7 miles) Nice 'n simple. .NET 4.5 Only Note that DbGeography and DbGeometry are exclusive to Entity Framework 5.0 (not 4.4 which ships in the same NuGet package or installer) and requires .NET 4.5. That's because the new DbGeometry and DbGeography (and related) types are defined in the 4.5 version of System.Data.Entity which is a CLR assembly and is only updated by major versions of .NET. Why this decision was made to add these types to System.Data.Entity rather than to the frequently updated EntityFramework assembly that would have possibly made this work in .NET 4.0 is beyond me, especially given that there are no native .NET framework spatial types to begin with. I find it also odd that there is no native CLR spatial type. The DbGeography and DbGeometry types are specific to Entity Framework and live on those assemblies. They will also work for general purpose, non-database spatial data manipulation, but then you are forced into having a dependency on System.Data.Entity, which seems a bit silly. There's also a System.Spatial assembly that's apparently part of WCF Data Services which in turn don't work with Entity framework. Another example of multiple teams at Microsoft not communicating and implementing the same functionality (differently) in several different places. Perplexed as a I may be, for EF specific code the Entity framework specific types are easy to use and work well. Working with pre-.NET 4.5 Entity Framework and Spatial Data If you can't go to .NET 4.5 just yet you can also still use spatial features in Entity Framework, but it's a lot more work as you can't use the DbContext directly to manipulate the location data. You can still run raw SQL statements to write data into the database and retrieve results using the same TSQL syntax I showed earlier using Context.Database.ExecuteSqlCommand(). Here's code that you can use to add location data into the database:[TestMethod] public void RawSqlEfAddTest() { string sqlFormat = @"insert into GeoLocations( Location, Address) values ( geography::STGeomFromText('POINT({0} {1})', 4326),@p0 )"; var sql = string.Format(sqlFormat,-121.527200, 45.712113); Console.WriteLine(sql); var context = new GeoLocationContext(); Assert.IsTrue(context.Database.ExecuteSqlCommand(sql,"301 N. 15th Street") > 0); } Here I'm using the STGeomFromText() function to add the location data. Note that I'm using string.Format here, which usually would be a bad practice but is required here. I was unable to use ExecuteSqlCommand() and its named parameter syntax as the longitude and latitude parameters are embedded into a string. Rest assured it's required as the following does not work:string sqlFormat = @"insert into GeoLocations( Location, Address) values ( geography::STGeomFromText('POINT(@p0 @p1)', 4326),@p2 )";context.Database.ExecuteSqlCommand(sql, -121.527200, 45.712113, "301 N. 15th Street") Explicitly assigning the point value with string.format works however. There are a number of ways to query location data. You can't get the location data directly, but you can retrieve the point string (which can then be parsed to get Latitude and Longitude) and you can return calculated values like distance. Here's an example of how to retrieve some geo data into a resultset using EF's and SqlQuery method:[TestMethod] public void RawSqlEfQueryTest() { var sqlFormat = @" DECLARE @s geography SET @s = geography:: STGeomFromText('POINT({0} {1})' , 4326); SELECT Address, Location.ToString() as GeoString, @s.STDistance( Location) as Distance FROM GeoLocations ORDER BY Distance"; var sql = string.Format(sqlFormat, -121.527200, 45.712113); var context = new GeoLocationContext(); var locations = context.Database.SqlQuery<ResultData>(sql); Assert.IsTrue(locations.Count() > 0); foreach (var location in locations) { Console.WriteLine(location.Address + " " + location.GeoString + " " + location.Distance); } } public class ResultData { public string GeoString { get; set; } public double Distance { get; set; } public string Address { get; set; } } Hopefully you don't have to resort to this approach as it's fairly limited. Using the new DbGeography/DbGeometry types makes this sort of thing so much easier. When I had to use code like this before I typically ended up retrieving data pks only and then running another query with just the PKs to retrieve the actual underlying DbContext entities. This was very inefficient and tedious but it did work. Summary For the current project I'm working on we actually made the switch to .NET 4.5 purely for the spatial features in EF 5.0. This app heavily relies on spatial queries and it was worth taking a chance with pre-release code to get this ease of integration as opposed to manually falling back to stored procedures or raw SQL string queries to return spatial specific queries. Using native Entity Framework code makes life a lot easier than the alternatives. It might be a late addition to Entity Framework, but it sure makes location calculations and storage easy. Where do you want to go today? ;-) Resources Download Sample Project© Rick Strahl, West Wind Technologies, 2005-2012Posted in ADO.NET  Sql Server  .NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

  Read the article

• Automapper: Handling NULL members

  - by PSteele

  A question about null members came up on the Automapper mailing list.  While the problem wasn’t with Automapper, investigating the issue led to an interesting feature in Automapper. Normally, Automapper ignores null members.  After all, what is there really to do?  Imagine these source classes: public class Source { public int Data { get; set; } public Address Address { get; set; } }   public class Destination { public string Data { get; set; } public Address Address { get; set; } }   public class Address { public string AddressType { get; set; } public string Location { get; set; } } And imagine a simple mapping example with these classes: Mapper.CreateMap<Source, Destination>();   var source = new Source { Data = 22, Address = new Address { AddressType = "Home", Location = "Michigan", }, };   var dest = Mapper.Map<Source, Destination>(source); The variable ‘dest’ would have a complete mapping of the Data member and the Address member. But what if the source had no address? Mapper.CreateMap<Source, Destination>();   var source = new Source { Data = 22, };   var dest = Mapper.Map<Source, Destination>(source); In that case, Automapper would just leave the Destination.Address member null as well.  But what if we always wanted an Address defined – even if it’s just got some default data?  Use the “NullSubstitute” option: Mapper.CreateMap<Source, Destination>() .ForMember(d => d.Address, o => o.NullSubstitute(new Address { AddressType = "Unknown", Location = "Unknown", }));   var source = new Source { Data = 22, };   var dest = Mapper.Map<Source, Destination>(source); Now, the ‘dest’ variable will have an Address defined with a type and location of “Unknown”.  Very handy! Technorati Tags: .NET,Automapper,NULL

  Read the article

• Best methods for Lazy Initialization with properties

  - by Stuart Pegg

  I'm currently altering a widely used class to move as much of the expensive initialization from the class constructor into Lazy Initialized properties. Below is an example (in c#): Before: public class ClassA { public readonly ClassB B; public void ClassA() { B = new ClassB(); } } After: public class ClassA { private ClassB _b; public ClassB B { get { if (_b == null) { _b = new ClassB(); } return _b; } } } There are a fair few more of these properties in the class I'm altering, and some are not used in certain contexts (hence the Laziness), but if they are used they're likely to be called repeatedly. Unfortunately, the properties are often also used inside the class. This means there is a potential for the private variable (_b) to be used directly by a method without it being initialized. Is there a way to make only the public property (B) available inside the class, or even an alternative method with the same initialized-when-needed?

  Read the article

• Metro: Namespaces and Modules

  - by Stephen.Walther

  The goal of this blog entry is to describe how you can use the Windows JavaScript (WinJS) library to create namespaces. In particular, you learn how to use the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. You also learn how to hide private methods by using the module pattern. Why Do We Need Namespaces? Before we do anything else, we should start by answering the question: Why do we need namespaces? What function do they serve? Do they just add needless complexity to our Metro applications? After all, plenty of JavaScript libraries do just fine without introducing support for namespaces. For example, jQuery has no support for namespaces and jQuery is the most popular JavaScript library in the universe. If jQuery can do without namespaces, why do we need to worry about namespaces at all? Namespaces perform two functions in a programming language. First, namespaces prevent naming collisions. In other words, namespaces enable you to create more than one object with the same name without conflict. For example, imagine that two companies – company A and company B – both want to make a JavaScript shopping cart control and both companies want to name the control ShoppingCart. By creating a CompanyA namespace and CompanyB namespace, both companies can create a ShoppingCart control: a CompanyA.ShoppingCart and a CompanyB.ShoppingCart control. The second function of a namespace is organization. Namespaces are used to group related functionality even when the functionality is defined in different physical files. For example, I know that all of the methods in the WinJS library related to working with classes can be found in the WinJS.Class namespace. Namespaces make it easier to understand the functionality available in a library. If you are building a simple JavaScript application then you won’t have much reason to care about namespaces. If you need to use multiple libraries written by different people then namespaces become very important. Using WinJS.Namespace.define() In the WinJS library, the most basic method of creating a namespace is to use the WinJS.Namespace.define() method. This method enables you to declare a namespace (of arbitrary depth). The WinJS.Namespace.define() method has the following parameters: · name – A string representing the name of the new namespace. You can add nested namespace by using dot notation · members – An optional collection of objects to add to the new namespace For example, the following code sample declares two new namespaces named CompanyA and CompanyB.Controls. Both namespaces contain a ShoppingCart object which has a checkout() method: // Create CompanyA namespace with ShoppingCart WinJS.Namespace.define("CompanyA"); CompanyA.ShoppingCart = { checkout: function (){ return "Checking out from A"; } }; // Create CompanyB.Controls namespace with ShoppingCart WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); // Call CompanyA ShoppingCart checkout method console.log(CompanyA.ShoppingCart.checkout()); // Writes "Checking out from A" // Call CompanyB.Controls checkout method console.log(CompanyB.Controls.ShoppingCart.checkout()); // Writes "Checking out from B" In the code above, the CompanyA namespace is created by calling WinJS.Namespace.define(“CompanyA”). Next, the ShoppingCart is added to this namespace. The namespace is defined and an object is added to the namespace in separate lines of code. A different approach is taken in the case of the CompanyB.Controls namespace. The namespace is created and the ShoppingCart object is added to the namespace with the following single line of code: WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); Notice that CompanyB.Controls is a nested namespace. The top level namespace CompanyB contains the namespace Controls. You can declare a nested namespace using dot notation and the WinJS library handles the details of creating one namespace within the other. After the namespaces have been defined, you can use either of the two shopping cart controls. You call CompanyA.ShoppingCart.checkout() or you can call CompanyB.Controls.ShoppingCart.checkout(). Using WinJS.Namespace.defineWithParent() The WinJS.Namespace.defineWithParent() method is similar to the WinJS.Namespace.define() method. Both methods enable you to define a new namespace. The difference is that the defineWithParent() method enables you to add a new namespace to an existing namespace. The WinJS.Namespace.defineWithParent() method has the following parameters: · parentNamespace – An object which represents a parent namespace · name – A string representing the new namespace to add to the parent namespace · members – An optional collection of objects to add to the new namespace The following code sample demonstrates how you can create a root namespace named CompanyA and add a Controls child namespace to the CompanyA parent namespace: WinJS.Namespace.define("CompanyA"); WinJS.Namespace.defineWithParent(CompanyA, "Controls", { ShoppingCart: { checkout: function () { return "Checking out"; } } } ); console.log(CompanyA.Controls.ShoppingCart.checkout()); // Writes "Checking out" One significant advantage of using the defineWithParent() method over the define() method is the defineWithParent() method is strongly-typed. In other words, you use an object to represent the base namespace instead of a string. If you misspell the name of the object (CompnyA) then you get a runtime error. Using the Module Pattern When you are building a JavaScript library, you want to be able to create both public and private methods. Some methods, the public methods, are intended to be used by consumers of your JavaScript library. The public methods act as your library’s public API. Other methods, the private methods, are not intended for public consumption. Instead, these methods are internal methods required to get the library to function. You don’t want people calling these internal methods because you might need to change them in the future. JavaScript does not support access modifiers. You can’t mark an object or method as public or private. Anyone gets to call any method and anyone gets to interact with any object. The only mechanism for encapsulating (hiding) methods and objects in JavaScript is to take advantage of functions. In JavaScript, a function determines variable scope. A JavaScript variable either has global scope – it is available everywhere – or it has function scope – it is available only within a function. If you want to hide an object or method then you need to place it within a function. For example, the following code contains a function named doSomething() which contains a nested function named doSomethingElse(): function doSomething() { console.log("doSomething"); function doSomethingElse() { console.log("doSomethingElse"); } } doSomething(); // Writes "doSomething" doSomethingElse(); // Throws ReferenceError You can call doSomethingElse() only within the doSomething() function. The doSomethingElse() function is encapsulated in the doSomething() function. The WinJS library takes advantage of function encapsulation to hide all of its internal methods. All of the WinJS methods are defined within self-executing anonymous functions. Everything is hidden by default. Public methods are exposed by explicitly adding the public methods to namespaces defined in the global scope. Imagine, for example, that I want a small library of utility methods. I want to create a method for calculating sales tax and a method for calculating the expected ship date of a product. The following library encapsulates the implementation of my library in a self-executing anonymous function: (function (global) { // Public method which calculates tax function calculateTax(price) { return calculateFederalTax(price) + calculateStateTax(price); } // Private method for calculating state tax function calculateStateTax(price) { return price * 0.08; } // Private method for calculating federal tax function calculateFederalTax(price) { return price * 0.02; } // Public method which returns the expected ship date function calculateShipDate(currentDate) { currentDate.setDate(currentDate.getDate() + 4); return currentDate; } // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); })(this); // Show expected ship date var shipDate = CompanyA.Utilities.calculateShipDate(new Date()); console.log(shipDate); // Show price + tax var price = 12.33; var tax = CompanyA.Utilities.calculateTax(price); console.log(price + tax); In the code above, the self-executing anonymous function contains four functions: calculateTax(), calculateStateTax(), calculateFederalTax(), and calculateShipDate(). The following statement is used to expose only the calcuateTax() and the calculateShipDate() functions: // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); Because the calculateTax() and calcuateShipDate() functions are added to the CompanyA.Utilities namespace, you can call these two methods outside of the self-executing function. These are the public methods of your library which form the public API. The calculateStateTax() and calculateFederalTax() methods, on the other hand, are forever hidden within the black hole of the self-executing function. These methods are encapsulated and can never be called outside of scope of the self-executing function. These are the internal methods of your library. Summary The goal of this blog entry was to describe why and how you use namespaces with the WinJS library. You learned how to define namespaces using both the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. We also discussed how to hide private members and expose public members using the module pattern.

  Read the article

• share one vpn connection through windows rras with other clients

  - by KTYP

  I'm having a Cisco VPN connection to access our branch office. Since several people using the VPN I'm planing to install the VPN client on one of our server and share it through RRAS to save the licenses (like site - to - site). I install RRAS on a windows 2008 R2 (svrw2k8r2) and made the static routes on client computers. I could able to ping to the VPN's IP on svrw2k8r2 server but they can't seems to connect to the servers in other branch through this setup. Below is my setup My Branch Server: svrw2k8r2 - Windows 2008 R2 IP: 192.168.40.100/24 VPN IP: 10.0.100.12/8 Clients Win7 IP: 192.168.40.101 - 110 / 24 Other Branch Servers IP:10.10.0.10-20/24

  Read the article

• Load balancing and HTTPS strategies

  - by Dan

  I am faced with the following problem: Servers get saturated since current load balancing strategy is based on client IP. Some corporate clients access our servers from behind large proxies so all clients appear with same IP to our load balancer. I think we are using some hardware load balancing device (can investigate further if necessary). We need to maintain session affinity (site is constructed in ASP), so all requests with same IP get routed to the same node. Since all the communication goes over the HTTPS, no request data (like session Id) is available to balancer as a client discriminator. Is there a way to use some other data besides the IP to distinguish between clients and route the clients even when coming from same IP to different nodes? Note: I need to maintain the traffic between the balancer and nodes safe (encrypted).

  Read the article

• Using DNS in iproute2

  - by Oliver

  In my setup I can redirect the default gateway based on the source address. Let's say a user is connected through tun0 (10.2.0.0/16) is redirect to another vpn. That works fine! ip rule add from 10.2.0.10 lookup vpn1 In a second rule I redirect the default gateway to another gateway if the user access a certain ip adress: ip rule add from 10.2.0.10 to 94.142.154.71 lookup vpn2 If I access the page on 94.142.154.71 (myip.is) the user is correctly routed and I can see the ip of the second vpn. On any other pages the ip address of vpn1 is shown. But how do I tell iproute2 that all request at e. g. google.com should be redirected through vpn2?

  Read the article

• The SIP Forum and the i3 Forum Team to Tame FoIP

  Long viewed as an ugly stepchild, fax over IP needs to be deployed reliably if the migration to IP communications is to succeed.

  Read the article

• how to point godaddy to my entrydns domain

  - by geminiCoder

  I have a server connected via dynamic ip. I have set up entrydns to manage the change of my ip. If I put in my entrydns url it points me to my servers current ip. I purchased a domain from go daddy, but I have been unable to get it to point to my entrydns. What I want is to be able to ssh to my server. but ideally id like to do this by using my domain name. I must confess Im a bit overwhelmed by the godaddy interface. So The bottom line is how do I point my godaddy domain to my dns domain so that when I look up the domain I get the current ip of the server?

  Read the article

• Cisco VPN disconnects after 5 seconds with error 422

  - by Marius

  I'm trying to connect to my university's server with VPN using Cisco VPN Client version 5.0.04, but after 5 seconds it disconnects with the error message 422: Lost contact with the secure gateway. Check your connection. From my research on the net it seems this could be because it tries to find my IP, and finds out that this is 127.0.0.1. Then 5 seconds later it discovers that I have a new IP (my actual IP), and it disconnects because I'm not allowed to change IP. Does anyone know how I could fix this, or if there is another reason i get this error? Update I looked through the log, and found this error, which confirms what I thought, except it gets the correct IP first, then changes it to localhost. 87 18:56:53.250 08/24/09 Sev=Warning/3 CM/0xA3100027 Adapter address changed from 149.171.237.25. Current address(es): 127.0.0.1.

  Read the article

• Email sent from server with rDNS & SPF being blocked by Hotmail

  - by Canadaka

  I have been unable to send email to users on hotmail or other Microsoft email servers for some time. Its been a major headache trying to find out why and how to fix the issue. The emails being sent that are blocked from my domain canadaka.net. I use Google Aps to host my regular email serverice for my @canadaka.net email addresses. I can sent email from my desktop or gmail to a hotmail without any problem. But any email sent from my server on behalf of canadaka.net is blocked, not even arriving in the junk email. The IP that the emails are being sent from is the same IP that my site is hosted on: 66.199.162.177 This IP is new to me since August 2010, I had a different IP for the previous 3-4 years. This IP is not on any credible spam lists http://www.anti-abuse.org/multi-rbl-check-results/?host=66.199.162.177 The one list spamcannibal.org my IP is listed on seems to be out of my control, says "no reverse DNS, MX host should have rDNS - RFC1912 2.1". But since I use Google for my email hosting, I don't have control over setting up RDNS for all the MX records. I do have Reverse DNS setup for my IP though, it resolves to "mail.canadaka.net". I have signed up for SNDS and was approved. My ip says "All of the specified IPs have normal status." Sender Score: 100 https://www.senderscore.org/lookup.php?lookup=66.199.162.177&ipLookup.x=55&ipLookup.y=14 My Mcafee threat level seems fine I have a TXT SPF record setup, I am currently using xname.org as my DNS, and they don't have a field for SPF, but their FAQ says to add the SPF info as a TXT entry. v=spf1 a include:_spf.google.com ~all Some "SPF checking" tools ive used detect that my domain has a valid SPF, but others don't. Like Microsoft's SPF wizard, i think this is because its specifically looking for an SPF record and not in the TXT. "No SPF Record Found. A and MX Records Available". From my home I can run "nslookup -type=TXT canadaka.net" and it returns: Server: google-public-dns-a.google.com Address: 8.8.8.8 Non-authoritative answer: canadaka.net text = "v=spf1 a include:_spf.google.com ~all" One strange thing I found is i'm unable to ping hotmail.com or msn.com or do a "telnet mail.hotmail.com 25". I am able to ping gmail.com and many other domains I tried. I tried changing my DNS servers to Google's Public DNS and did a ipconfig /flushdns but that had no effect. I am however able to connect with telnet to mx1.hotmail.com This is what the email headers look like when I send to a Google email server and I receive the email with no troubles. You can see that SPF is passing. Delivered-To: [email protected] Received: by 10.146.168.12 with SMTP id q12cs91243yae; Sun, 27 Feb 2011 18:01:49 -0800 (PST) Received: by 10.43.48.7 with SMTP id uu7mr4292541icb.68.1298858509242; Sun, 27 Feb 2011 18:01:49 -0800 (PST) Return-Path: Received: from canadaka.net ([66.199.162.177]) by mx.google.com with ESMTP id uh9si8493137icb.127.2011.02.27.18.01.45; Sun, 27 Feb 2011 18:01:48 -0800 (PST) Received-SPF: pass (google.com: domain of [email protected] designates 66.199.162.177 as permitted sender) client-ip=66.199.162.177; Authentication-Results: mx.google.com; spf=pass (google.com: domain of [email protected] designates 66.199.162.177 as permitted sender) [email protected] Message-Id: <[email protected] Received: from coruscant ([127.0.0.1]:12907) by canadaka.net with [XMail 1.27 ESMTP Server] id for from ; Sun, 27 Feb 2011 18:01:29 -0800 Date: Sun, 27 Feb 2011 18:01:29 -0800 Subject: Test To: [email protected] From: XXXX Reply-To: [email protected] X-Mailer: PHP/5.2.13 I can send to gmail and other email services fine. I don't know what i'm doing wrong! UPDATE 1 I have been removed from hotmails IP block and am now able to send emails to hotmail, but they are all going directly to the JUNK folder. UPDATE 2 I used Telnet to send a test message to port25.com, seems my SPF is not being detected. Result: neutral (SPF-Result: None) canadaka.net. SPF (no records) canadaka.net. TXT (no records) I do have a TXT record, its been there for years, I did change it a week ago. Other sites that allow you to check your SPF detect it, but some others like Microsofts Wizard doesn't. This iw what my SPF record in my xname.org DNS file looks like: canadaka.net. 86400 IN TXT "v=spf1 a include:_spf.google.com ~all" I did have a nameserver as my 4th option that doens't have the TXT records since it doens't support it. So I removed it from the list and instead added wtfdns.com as my 4th adn 5th nameservers, which does support TXT.

  Read the article

• Getting to grips with the stack in nasm

  - by MarkPearl

  Today I spent a good part of my day getting to grips with the stack and nasm. After looking at my notes on nasm I think this is one area for the course I am doing they could focus more on… So here are some snippets I have put together that have helped me understand a little bit about the stack… Simplest example of the stack You will probably see examples like the following in circulation… these demonstrate the simplest use of the stack… org 0x100 bits 16 jmp main main: push 42h push 43h push 44h mov ah,2h ;set to display characters pop dx    ;get the first value int 21h   ;and display it pop dx    ;get 2nd value int 21h   ;and display it pop dx    ;get 3rd value int 21h   ;and display it int 20h The output from above code would be… DCB Decoupling code using “call” and “ret” This is great, but it oversimplifies what I want to use the stack for… I do not know if this goes against the grain of assembly programmers or not, but I want to write loosely coupled assembly code – and I want to use the stack as a mechanism for passing values into my decoupled code. In nasm we have the call and return instructions, which provides a mechanism for decoupling code, for example the following could be done… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h mov dx,41h int 21h ret ;---------------------------------------- main: call displayChar int 20h   This would output the following to the console A So, it would seem that call and ret allow us to jump to segments of our code and then return back to the calling position – a form of segmenting the code into what we would called in higher order languages “functions” or “methods”. The only issue is, in higher order languages there is a way to pass parameters into the functions and return results. Because of the primitive nature of the call and ret instructions, this does not seem to be obvious. We could of course use the registers to pass values into the subroutine and set values coming out, but the problem with this is we… Have a limited number of registers Are threading our code with tight coupling (it would be hard to migrate methods outside of their intended use in a particular program to another one) With that in mind, I turn to the stack to provide a loosely coupled way of calling subroutines… First attempt with the Stack Initially I thought this would be simple… we could use code that looks as follows to achieve what I want… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h pop dx int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h   However running this application does not give the desired result, I want an ‘A’ to be returned, and I am getting something totally different (you will to). Reading up on the call and ret instructions a discovery is made… they are pushing and popping things onto and off the stack as well… When the call instruction is executed, the current value of IP (the address of the instruction to follow) is pushed onto the stack, when ret is called, the last value on the stack is popped off into the IP register. In effect what the above code is doing is as follows with the stack… push 41h push current value of ip pop current value of ip to dx pop 41h to ip This is not what I want, I need to access the 41h that I pushed onto the stack, but the call value (which is necessary) is putting something in my way. So, what to do? Remember we have other registers we can use as well as a thing called indirect addressing… So, after some reading around, I came up with the following approach using indirect addressing… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h In essence, what I have done here is used a trick with the stack pointer… it goes as follows… Push 41 onto the stack Make the call to the function, which will push the IP register onto the stack and then jump to the displayChar label Move the value in the stack point to the bp register (sp currently points at IP register) Move the at the location of bp minus 2 bytes to dx (this is now the value 41h) display it, execute the ret instruction, which pops the ip value off the stack and goes back to the calling point This approach is still very raw, some further reading around shows that I should be pushing the value of bp onto the stack before replacing it with sp, but it is the starting thread to getting loosely coupled subroutines. Let’s see if you get what the following output would be? org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+4] int 21h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h push 42h call displayChar int 20h The output is… AB Where to from here? If by any luck some assembly programmer comes along and see this code and notices that I have made some fundamental flaw in my logic… I would like to know, so please leave a comment… appreciate any feedback!

  Read the article

• Setting alias for DynDNS domain

  - by metalball

  Hey all, I've created DynDNS domain for testing my local sites, and i'm having trouble with pointing to root domain. From my registrar (GoDaddy) I've created a CNAME for www to point my example.dyndns.com so going to url www.example.com I'm reaching my site. But if I'm going to example.com I'm reaching to the IP of the A record. I can't set the IP for the A record to be my IP because I have dynamic IP, and it changes constatly, and I can't point the A record to domain, only IP. When trying to create CNAME record @ to point example.dyndns.com I'm getting error "A record of a different type exists for the hostname @, could not create CNAME" The only record using the '@' host are NS record, which I can't delete, and when tried to set another NS record with @ point to example.dyndns.com, I've lost connection to my site :) So what can I do to get example.com url reach my site? Thanx!

  Read the article

• IIS replaces redirect status header from PHP with 302 Redirect

  - by IP

  Hello I hope I am posting this in the correct place... I'm having an issue with a 301 redirect in php. Looking at the headers, if I do a simple 301 redirect, it actually appears as a 302 redirect which is not what I am after. This is the php code: header("Status: 301 Moved Permanently"); header('Location: newurl'); It is running on the latest version of php, IIS7 and uses the FastCGI module (which is apparently where this bug could exist). A quick Google finds other people with the same problem, but no actual solution. http://www.mombu.com/php/bugs-forum/t-301-redirect-returning-302-instead-3090775.html http://forums.iis.net/p/1158431/1907156.aspx Many thanks! Paul

  Read the article

• freebsd ipfw tablearg.

  - by Shamanu4

  Hello. I'm configuring freebsd firewall and have such situation: 51000 pipe tablearg ip from not table(17) to table(20) out xmit ng* 51010 pipe tablearg ip from table(21) to not table(17) in recv ng* 51020 pipe tablearg ip from any to table(18) out xmit ng* 51030 pipe tablearg ip from table(19) to any in recv ng* tables 18,19,20,21 have client ip addresses and pipe numbers table 17 list of networks. rules 51020 and 51030 work fine but what is going at 51000 and 51010 ? How to determine firewall to take pipe number from tables 20 and 21 - not from 17 ?

  Read the article

• Calculated Columns in Entity Framework Code First Migrations

  - by David Paquette

  I had a couple people ask me about calculated properties / columns in Entity Framework this week.  The question was, is there a way to specify a property in my C# class that is the result of some calculation involving 2 properties of the same class.  For example, in my database, I store a FirstName and a LastName column and I would like a FullName property that is computed from the FirstName and LastName columns.  My initial answer was: 1: public string FullName 2: { 3: get { return string.Format("{0} {1}", FirstName, LastName); } 4: } Of course, this works fine, but this does not give us the ability to write queries using the FullName property.  For example, this query: 1: var users = context.Users.Where(u => u.FullName.Contains("anan")); Would result in the following NotSupportedException: The specified type member 'FullName' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported. It turns out there is a way to support this type of behavior with Entity Framework Code First Migrations by making use of Computed Columns in SQL Server.  While there is no native support for computed columns in Code First Migrations, we can manually configure our migration to use computed columns. Let’s start by defining our C# classes and DbContext: 1: public class UserProfile 2: { 3: public int Id { get; set; } 4: 5: public string FirstName { get; set; } 6: public string LastName { get; set; } 7: 8: [DatabaseGenerated(DatabaseGeneratedOption.Computed)] 9: public string FullName { get; private set; } 10: } 11: 12: public class UserContext : DbContext 13: { 14: public DbSet<UserProfile> Users { get; set; } 15: } The DatabaseGenerated attribute is needed on our FullName property.  This is a hint to let Entity Framework Code First know that the database will be computing this property for us. Next, we need to run 2 commands in the Package Manager Console.  First, run Enable-Migrations to enable Code First Migrations for the UserContext.  Next, run Add-Migration Initial to create an initial migration.  This will create a migration that creates the UserProfile table with 3 columns: FirstName, LastName, and FullName.  This is where we need to make a small change.  Instead of allowing Code First Migrations to create the FullName property, we will manually add that column as a computed column. 1: public partial class Initial : DbMigration 2: { 3: public override void Up() 4: { 5: CreateTable( 6: "dbo.UserProfiles", 7: c => new 8: { 9: Id = c.Int(nullable: false, identity: true), 10: FirstName = c.String(), 11: LastName = c.String(), 12: //FullName = c.String(), 13: }) 14: .PrimaryKey(t => t.Id); 15: Sql("ALTER TABLE dbo.UserProfiles ADD FullName AS FirstName + ' ' + LastName"); 16: } 17: 18: 19: public override void Down() 20: { 21: DropTable("dbo.UserProfiles"); 22: } 23: } Finally, run the Update-Database command.  Now we can query for Users using the FullName property and that query will be executed on the database server.  However, we encounter another potential problem. Since the FullName property is calculated by the database, it will get out of sync on the object side as soon as we make a change to the FirstName or LastName property.  Luckily, we can have the best of both worlds here by also adding the calculation back to the getter on the FullName property: 1: [DatabaseGenerated(DatabaseGeneratedOption.Computed)] 2: public string FullName 3: { 4: get { return FirstName + " " + LastName; } 5: private set 6: { 7: //Just need this here to trick EF 8: } 9: } Now we can both query for Users using the FullName property and we also won’t need to worry about the FullName property being out of sync with the FirstName and LastName properties.  When we run this code: 1: using(UserContext context = new UserContext()) 2: { 3: UserProfile userProfile = new UserProfile {FirstName = "Chanandler", LastName = "Bong"}; 4: 5: Console.WriteLine("Before saving: " + userProfile.FullName); 6: 7: context.Users.Add(userProfile); 8: context.SaveChanges(); 9:  10: Console.WriteLine("After saving: " + userProfile.FullName); 11:  12: UserProfile chanandler = context.Users.First(u => u.FullName == "Chanandler Bong"); 13: Console.WriteLine("After reading: " + chanandler.FullName); 14:  15: chanandler.FirstName = "Chandler"; 16: chanandler.LastName = "Bing"; 17:  18: Console.WriteLine("After changing: " + chanandler.FullName); 19:  20: } We get this output: It took a bit of work, but finally Chandler’s TV Guide can be delivered to the right person. The obvious downside to this implementation is that the FullName calculation is duplicated in the database and in the UserProfile class. This sample was written using Visual Studio 2012 and Entity Framework 5. Download the source code here.

  Read the article

• rhel/centos vs. ubuntu (possibly other debian-based systems) linux in handling duplicate ips in the same subnet

  - by johnshen64

  This has bothered me for quite a while but I never found out why or how to change the behavior. ip duplicates could be caused by typos or dhcp errors etc., but they do occur from time to time. in rpm-based systems such as centos, the old server with the duplicate ip wins, and the new server will get an error in bringing up the nic (ip address already used). this is somewhat harmless because we can just fix the system that is coming up. ubuntu only the other hand happily grabs the used ip for itself and leave the old server/device without a valid ip. this is the more dangerous behavior because it causes outages. what i want is to change the ubuntu behavior to that of the centos/rhel so would appreciate any help.

  Read the article

• Problems with Level Architect, Citrus Engine, Flash

  - by Idan

  I am using the Citrus Engine to make a Flash game, and the Level Architect doesn't work well for me. Firstly, when I first launch it and open my project and my level, nothing is shown, no assets and not anything I have previously done with my level. To fix it, I open another project. The other project works fine, meaning I can see the assets and the level. Then I go back to the actual project I am working on, and the problem is fixed, only it does not fix the second problem: I can't add my own assests. I follow the manual and add tags like this: [Property(value="0")] But it doesn't change a thing in the level architect window (even after I close and reopen it). Any ideas? Thanks! Here's the code of the class I want to be shown in the Level Architect: package { import com.citrusengine.objects.PhysicsObject; import com.citrusengine.objects.platformer.Sensor; import flash.utils.clearTimeout; import flash.utils.setTimeout; /** * @author Aymeric */ public class Teleporter extends Sensor { [Property(value="0")] public var endX:Number=0; [Property(value="0")] public var endY:Number=0; public var object:PhysicsObject; [Property(value="0")] public var time:Number = 0; public var needToTeleport:Boolean = false; protected var _teleporting:Boolean = false; private var _teleportTimeoutID:uint; public function Teleporter(name:String, params:Object = null) { super(name, params); } override public function destroy():void { clearTimeout(_teleportTimeoutID); super.destroy(); } override public function update(timeDelta:Number):void { super.update(timeDelta); if (needToTeleport) { _teleporting = true; _teleportTimeoutID = setTimeout(_teleport, time); needToTeleport = false; } _updateAnimation(); } protected function _teleport():void { _teleporting = false; object.x = endX; object.y = endY; clearTimeout(_teleportTimeoutID); } protected function _updateAnimation():void { if (_teleporting) { _animation = "teleport"; } else { _animation = "normal"; } } } }

  Read the article

• Vmware sphere setting up external network

  - by Tom Beech

  I've just setup vmware vsphere 5 on a remote server (rented dedicated server). I've added my first VPS (centos 5.8) barebones. It's not finding any IP (internal or external) on boot. I've had an extra external IP assigned to my server that I wanted to use on the VPS. I tried editing the eth0 config and adding the IP in there and turning off the DHCP, but it can't find any IP or ping google or do any networking type things. How do I route the IP to my VPS so I can access it remotely?

  Read the article

• DNS question and Google PageRank from domains

  - by Beck

  I'm not so good at dns at all :) Just basics. A while ago i have noticed, that my blog have different Page Ranks, PR 3 for domain www.example.com and PR 1 for domain example.com. In dns records i have this setup: A - IP - www.example.com A - same IP - example.com Should i replace this record "A - same IP - example.com" with row with CNAME instead of A? Like that: CNAME - same IP - example.com - alias www.example.com Will this combine Page Rank value of both domains? Or i can just create 302 redirection inside .htaccess file, verify example.com(without www) inside Google Webmaster Tools as my domain and inside www.example.com options set as main domain? Thanks ;)

  Read the article

• Ubuntu server 12.04 E: Unable to locate package noip2

  - by cesar

  I just Installed Ubuntu server 12.04 and I want to install no-ip I ran as root: sudo apt-get install noip2 and I got this: root@topcat:/var# sudo apt-get install noip2 Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package noip2 I also tried with:wget htt://www.no-ip.com/client/linux/noip-duc-linux.tar.gz but I got: wget: unable to resolve host address `www.no-ip.com' Does somebody can help me?, I am new in Ubuntu

  Read the article

• Bonding: works only from one link

  - by Crazy_Bash

  I would like to install bonding with 4 links. but only one of them is active. eth4 is always active. the others simply don't work. those are my configs: DEVICE="eth2" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth3" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth4" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth5" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE=bond0 IPADDR=<ip> BROADCAST=<ip> NETWORK=<ip> GATEWAY=<ip> NETMASK=<ip> USERCTL=no BOOTPROTO=none ONBOOT=yes NM_CONTROLLED=no /etc/modprobe.d/bonding.conf alias bond0 bonding options bond0 mode=4 miimon=100 updelay=200 #downdelay=200 xmit_hash_policy=layer3+4 lacp_rate=1 Linux: Linux 3.0.0+ #1 SMP Fri Oct 26 07:55:47 EEST 2012 x86_64 x86_64 x86_64 GNU/Linux what i've tried: downdelay=200 xmit_hash_policy=layer3+4 lacp_rate=1

  Read the article

< Previous Page | 171 172 173 174 175 176 177 178 179 180 181 182  | Next Page >