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  • I'm looking for a monitor tool to test Jitter, ICMP, Traceroute and other network issues

    - by Elad Dotan
    I'm looking for a monitor tool to test Jitter, ICMP, Traceroute and other network issues. it could be an application I run from my company Network in NY and London or a SAAS service that have a service that can do it for me. I have a problem in my Data Center that I would like to fix. it happens in different times of the day. I want to run the monitor for few days and save the results so we can analyze them. any idea? Thanks!! Elad.

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  • Any way to know if two ip address points to the same machine?

    - by Vivek V K
    Is there anyway to find if two different IP address in two different network actually points to the same physical device? I need it in Linux. Edit - I have the same server(a raspberry pi) connected via 2 intranets to my client. I don't know the IP address of the server as it is DHCP. The crude way to do is to reach the raspberry pi from one intranet and check with ifconfig to find the ipadress of the machine in the other Intranet. I want to know if there is any other way I can do it? I know the mac address of the machine.But I don't know how do I find the Ipadress based on the mac address.

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  • Why is my eth0 getting a dynamic ip when it is configured to be static?

    - by sdek
    For some reason our office linux box is being assigned an ip address via dhcp and I don't know why. What is confusing to me is that when I check system-config-network it shows that my eth0 is setup to be a static ip address. And /etc/sysconfig/network-scripts/ifcfg-eth0 also shows it is setup to be a static ip, yet it is getting a different ip address than the one specified in the ifcfg-eth0. Let me know if you have any suggestions on or ideas on where I can look next. Here are a few details that might help you figure out what an idiot I am :) Fedora 11 Router in front of this box is running dhcp, starting at 10.42.1.100 This box is configured to be 10.42.1.50 (at least I think it is!), subnet 255.255.255.0 (which is same as the router's lan subnet) Instead of having the static IP, this box is getting assigned 10.42.1.100. Here are the ifcfg-eth0 details DEVICE=eth0 BOOTPROTO=none ONBOOT=yes TYPE=Ethernet USERCTL=no NM_CONTROLLED=no NETMASK=255.255.255.0 IPADDR=10.42.1.50 GATEWAY=10.42.1.1

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  • 3 Servers, 2 Work Fine, One Has Network Issues

    - by ScaleOvenStove
    i have 3 servers, all relatively the same hardware/config, etc. I run some data pulls on all 3, and on 2 of them, they have 1 nic, and they work fine. On the other , there are 2 nics, and unless they are both plugged in or teamed, the processes time out. Any ideas on why this would be? It doesn't make sense to me, as the other two work fine with 1 nic and don't time out when running the same processes.

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  • Windows 7 VPN Error 619

    - by TravisPUK
    So I am running Windows 7 Enterprise. This morning I was able to VPN using the built in VPN (Connect to Work Network etc). I had to change my network's IP address range and now the VPN will not work. It just stalls on the Verifying user name and password... message. But then it returns the 619 error. Anybody know why changing my machine's IP address would cause this problem? Where should I be looking to try and fix this issue? I have tried this on a Windows XP machine that also had the IP address range change and this still connects fine using exactly the same connection details. EDIT The internal network range changed from 192.x.x.x to 10.x.x.x. This was done on the entire Active Directory. All machines are running fine and the Windows XP machine, that works going to the same client VPN mentioned above is on the same network. Both the XP and the Win 7 machines are using DHCP served by the Domain Controller. The client domain is not performing any IP range checks/restrictions. The VPN is outside the internal network, connection is being made via the Internet and not passing through any other machine, other than the normal domain machines, ie DNS etc. This is passing through a router and the router has the relevant VPN passthrough options configured. All internal machines are working correctly with other forms of VPN, ie Cisco, Sonic etc (these were tested on other machines, they are not installed on the Vista or Win7 machines). After further testing, this is occurring on all Win7 and Vista machines where they can no longer connect to the client VPN, however all XP machines can still connect fine. This has been tested on three Vista, two Win7 and five XP machines. All machines are on DHCP and tests have been done with both the firewalls turned on and off, as well as with fixed IPs being used. Thanks Travis

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  • Vlan and Switch setting - dummy

    - by Andras Sebestyen
    I need to speak tomorrow the network engineer and I would like to understand his so apologise for the Dummy question: In the school we have a cab with a 24 port Netgear manageable switch with an admin and curriculum VLAN settings. Usually, as I over heard, in the morning and around 4.30pm there are a slowdown period on the computers which connect to this switch. No one could track this back yet. Questions: What is the best way to track back this slowdown Would it be a temporary solution to physical separate the two network with 2 switches If that would work how can I link them together to be able to see the curriculum from the admin side. Do I need an extra router then? Too many questions but I have no clue where to start and the gentleman will be paid by hours... can you see where I am coming from?:) Could you guide me in the right direction please? Any comment would be appreciated and please send links if you down vote the question:)

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  • Cannot access server shares over VPN

    - by DuncanDavies
    I've set up a single hosted server to use as a development environment for a web-based application. The web app is served up fine on port 80, however I'm struggling to get my VPN to behave how I'd expect so the developers don't have the access they require. The VPN connects fine and I can access the back-end database (SQL Server) which resides on the server with the client tools from the laptops. However they cannot access any shared folders. The server's local IP address is 10.x.x.x, and I've assigned a static IP address pool to RRAS (of 192.168.100.1 - 20). The clients pick up a valid IP Address (i.e. 192.168.100.9) when they connect. There is no name resolution setup, DNS or WINS. When connected via VPN the clients can ping the server (192.168.100.1) by IP Address, but cannot map a drive to a shared folder (net use * \\192.168.100.1\xxxxx) - I get 'System error 53 has occurred. The network path was not found.' I don't understand why I can ping by the ip, but not map by it. Some details: Server OS is Windows 2008 (Datacenter) VPN is SSTP using RRAS Clients are all Windows 7 I've tried temporarily disabling the firewalls So, why can we not access the file system when everything else (ping, RDP, SQL Server clients tools) works? Thanks for your help Duncan

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  • Getting Wireless working on Dell Inspiron 1545 in Ubuntu 10.04?

    - by Dexter
    I'm trying to install my wireless drivers (which uses a broadcom card). I tried to install them using the restricted drivers offered on my Ubuntu CD. However when I clicked activate it got about halfway through the install process before it gave me this error message: SystemError: installArchives() failed How can I correct this?

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  • What software do you use to detect an internect connection drop?

    - by Darryl Hein
    I'm looking for a piece of software to detect drops in my internet connection and log those drops. OS doesn't really matter since I have pretty much everything running here, although something on OSX would be nice. I also don't really care how it determines that connection has been dropped, but I think that there must be something better than a ping or at least a combination of a ping and something else.

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  • Cannot Resolve Host Or Access Website Through Router

    - by Boris_yo
    This is weird. I am on Windows XP with Edimax BR 6204Wg. I have 3 devices - 2 laptops and 1 smartphone. 1st laptop and smartphone are connected through WiFi to router and 2nd laptop is connected through LAN to router. Before firmware upgrade i did not try to access website but after firmware upgrade to latest version: http://www.edimax.eu/en/support_detail.php?pd_id=11&pl1_id=3#02 i had problems resolving host, pinging, tracerting and accessing website. Sometimes ping and tracert work but i cannot access website and sometimes i can access website but ping and tracert do not work. Weird? I downgraded to previous version and no changes. If i can no longer access that website through Internet Explorer, i can access it in Firefox. I tried deleting cookies, clearing cache and that seem not make difference. Switching LAN port did not make difference. When i disconnect router and connect laptop through LAN to internet modem, everything is normal. I tried resetting router, resetting to factory default settings and all did not help. At the moment i can access website on laptop connected through LAN from Firefox and Internet Explorer, but on my smartphone i can access website only with Opera but not with built-in browser and Skyfire. UPDATE: I just could only access with Internet Explorer but not with other browsers on my PC. Minutes later i could access with all browsers. But on smartphone i could only access with Opera and not with other browsers. I am confused. I also determined that sometimes i can access and sometimes can't. What is also weird is that when ping and tracert cannot resolve host, i still am able to access website.

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  • traffic shaping for certain (local) users

    - by JMW
    Hello, i'm using ubuntu 10.10 i've a local backup user called "backup". :) i would like to give this user just a bandwidth of 1Mbit. No matter which software wants to connect to the network. this solution doesn't work: iptables -t mangle -A OUTPUT -p tcp -m owner --uid-owner 1001 -j MARK --set-mark 12 iptables -t mangle -A POSTROUTING -p tcp -m owner --uid-owner 1001 -j MARK --set-mark 12 tc qdisc del dev eth0 root tc qdisc add dev eth0 root handle 2 htb default 1 tc filter add dev eth0 parent 2: protocol ip pref 2 handle 50 fw classid 2:6 tc class add dev eth0 parent 2: classid 2:6 htb rate 10Kbit ceil 1Mbit tc qdisc show dev eth0 tc class show dev eth0 tc filter show dev eth0 does anyone know how to do it? thanks a lot in advance

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  • Secure openVPN using IPTABLES

    - by bob franklin smith harriet
    Hey, I setup an openVPN server and it works ok. The next step is to secure it, I opted to use IPTABLES to only allow certain connections through but so far it is not working. I want to enable access to the network behind my openVPN server, and allow other services (web access), when iptables is disabaled or set to allow all this works fine, when using my following rules it does not. also note, I already configured openVPN itself to do what i want and it works fine, its only failing when iptables is started. Any help to tell me why this isnt working will appreciated here. These are the lines that I added in accordance with openVPN's recommendations, unfortunately testing these commands shows that they are requiered, they seem incredibly insecure though, any way to get around using them? # Allow TUN interface connections to OpenVPN server -A INPUT -i tun+ -j ACCEPT #allow TUN interface connections to be forwarded through other interfaces -A FORWARD -i tun+ -j ACCEPT # Allow TAP interface connections to OpenVPN server -A INPUT -i tap+ -j ACCEPT # Allow TAP interface connections to be forwarded through other interfaces -A FORWARD -i tap+ -j ACCEPT These are the new chains and commands i added to restrict access as much as possible unfortunately with these enabled, all that happens is the openVPN connection establishes fine, and then there is no access to the rest of the network behind the openVPN server note I am configuring the main iptables file and I am paranoid so all ports and ip addresses are altered, and -N etc appears before this so ignore that they dont appear. and i added some explanations of what i 'intended' these rules to do, so you dont waste time figuring out where i went wrong : 4 #accepts the vpn over port 1192 -A INPUT -p udp -m udp --dport 1192 -j ACCEPT -A INPUT -j INPUT-FIREWALL -A OUTPUT -j ACCEPT #packets that are to be forwarded from 10.10.1.0 network (all open vpn clients) to the internal network (192.168.5.0) jump to [sic]foward-firewall chain -A FORWARD -s 10.10.1.0/24 -d 192.168.5.0/24 -j FOWARD-FIREWALL #same as above, except for a different internal network -A FORWARD -s 10.10.1.0/24 -d 10.100.5.0/24 -j FOWARD-FIREWALL # reject any not from either of those two ranges -A FORWARD -j REJECT -A INPUT-FIREWALL -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT-FIREWALL -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT-FIREWALL -j REJECT -A FOWARD-FIREWALL -m state --state RELATED,ESTABLISHED -j ACCEPT #80 443 and 53 are accepted -A FOWARD-FIREWALL -m tcp -p tcp --dport 80 -j ACCEPT -A FOWARD-FIREWALL -m tcp -p tcp --dport 443 -j ACCEPT #192.168.5.150 = openVPN sever -A FOWARD-FIREWALL -m tcp -p tcp -d 192.168.5.150 --dport 53 -j ACCEPT -A FOWARD-FIREWALL -m udp -p udp -d 192.168.5.150 --dport 53 -j ACCEPT -A FOWARD-FIREWALL -j REJECT COMMIT now I wait :D

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  • Multicasting and multicast address

    - by Zia ur Rahman
    I have confusion about the multicast addresses, I have read an example which is given by. Suppose two applications have been built to send audio over a network. One application accepts and digitizes an audio input stream, and then sends the resulting frame across the network to other application. The second application receives the digitized audio from the network, converts it back to the audio signal and plays the result over a speaker. Unless the two applications use broadcast to send frames, no other computers on the network will receive a copy of the frame. Multicasting provides an excellent solution to the problems of allowing some computers to participate in audio transmission. To use multicasting , a multicast address must be chosen for the audio application. And the receiving application passes the multicast address to the network interface. The interface begins to accept the packets sent to that address. Question: how this multicast address is chosen, how the receiving application knows that the sender using this specific destination address for the audio frames.

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  • What does this UDP Packet mean ?

    - by asksuperuser
    I'm total newbie at tcp/ip and I was experimenting with Wireshark. What this mean: 1824 578.194204 xxx.xxx.xxx.xxx yyy.yyy.yyy.yyy UDP Source port: 17500 Destination port: 17500 In data I can see that my user pc name is sent (happily it's a generic name): does this mean someone is trying to hack my pc ?

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  • Managing an application across multiple servers, or PXE vs cfEngine/Chef/Puppet

    - by matt
    We have an application that is running on a few (5 or so and will grow) boxes. The hardware is identical in all the machines, and ideally the software would be as well. I have been managing them by hand up until now, and don't want to anymore (static ip addresses, disabling all necessary services, installing required packages...) . Can anyone balance the pros and cons of the following options, or suggest something more intelligent? 1: Individually install centos on all the boxes and manage the configs with chef/cfengine/puppet. This would be good, as I have wanted an excuse to learn to use one of applications, but I don't know if this is actually the best solution. 2: Make one box perfect and image it. Serve the image over PXE and whenever I want to make modifications, I can just reboot the boxes from a new image. How do cluster guys normally handle things like having mac addresses in the /etc/sysconfig/network-scripts/ifcfg* files? We use infiniband as well, and it also refuses to start if the hwaddr is wrong. Can these be correctly generated at boot? I'm leaning towards the PXE solution, but I think monitoring with munin or nagios will be a little more complicated with this. Anyone have experience with this type of problem? All the servers have SSDs in them and are fast and powerful. Thanks, matt.

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  • Cannot browse remote networks even with WINS configured

    - by paradroid
    As the NetBIOS protocol acts on Layer 2 and so is not routable, In order to enable network browsing of remote networks, WINS has been installed and configured on two domain controllers, both of which are on different networks. The WINS servers seem to be replicating with eachother, and each has 127.0.0.1 set as the Primary WINS Server in each of their LAN interface properties, with nothing entered for Secondary WINS Server. The DC which holds the PDC Emulator FSMO role has the Computer Browser service running and set to Auto start, and it has the WINS/NBT node type network setting at 0x8 (H-node - Hybrid node). Remote network browsing does not work. Is the WINS/NBT node type correct for this scenario? The reason why I think it may not be the right one is because I set the DHCP Server's 046 WINS/NBT node type option to 0x8 as well, after which the DHCP clients started to disappear from the Network folders. When that option is not set, does it default to B-node (Broadcast node)? Or could it be a problem with the WINS servers setup?

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  • How to block/avoid a particular IP when connecting to websites?

    - by Mark
    I'm having trouble connecting to a particular website. I can view it through a proxy, but not from home. So I ran a traceroute: Tracing route to fvringette.com [76.74.225.90] over a maximum of 30 hops: 1 <1 ms <1 ms <1 ms <snip> 2 * * * Request timed out. 3 9 ms 7 ms 27 ms rd2bb-ge2-0-0-22.vc.shawcable.net [64.59.146.226] 4 8 ms 7 ms 7 ms rc2bb-tge0-9-2-0.vc.shawcable.net [66.163.69.41] 5 10 ms 9 ms 9 ms rc2wh-tge0-0-1-0.vc.shawcable.net [66.163.69.65] 6 27 ms 23 ms 22 ms ge-gi0-2.pix.van.peer1.net [206.223.127.1] 7 18 ms 18 ms 20 ms 10ge.xe-0-2-0.van-spenc-dis-1.peer1.net [216.187.89.206] 8 9 ms 11 ms 10 ms 64.69.91.245 9 * * * Request timed out. 10 * * * Request timed out. ... Looks like this "64.69.91.245" is somehow blocking me. Can I tell my computer to avoid/bypass that IP when trying to connect?

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  • Crossover cable in addition to normal network connection on servers?

    - by Zero0ne
    I have 2 servers, both with Windows 2003 R2 Each have 2 NIC ports that are 10/100/1000 They are both connected to our LAN + joined to the domain (1 NIC port free on each server) The problem is that our main router is only 10/100 on the ports that these servers are connected to. Since one server is going to host SQL 2005 and the other will be running Altiris NS7, I was hoping that I could use a crossover cable to connect the two directly, thus taking advantage of their 1gbps NIC cards. Is this possible? If so what steps do I need to take to accomplish this? What needs to be done to make sure that when the app server is communicating with the SQL server that it is using the direct link vs traversing the LAN? Thanks a lot!

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  • how to broadcast a PXE server like Trinity Rescue Kit

    - by Larry G. Wapnitsky
    I would like to set up a portable PXE server for diagnostic purposes. The issue is that I won't always have access to the DHCP server, or the router itself (sometimes a home router) doesn't have an easily accessible place to set the servername/file for broadcast. I know that Trinity Rescue Kit is able to broadcast its PXE server without its own DHCP server. Can anyone point me in the direction to set this up on my own (without Trinity)? Thanks.

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  • How to share computer's internet connection among network users

    - by RBA
    I wanted to connect to internet from my mobile through laptop wireless-broadband internet connection.. For that I have gone to Network Places, there i have done appropriate settings for "Wireless Network Connection" and "Bluetooth Personal Area Network Connection",, but that Bluetooth connection is still not showing connected.. I have checked the option for "Allow other network users to connect through this computers Internet connection", but still my Bluetooth Connection is still showing not connected.. Please help me out,, as to how can i achieve the same,, as i am having Broadband internet connection, which comes wirelessly to my laptop through a router/modem..

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  • Make case-sensitive SMB share case-insensitive

    - by fungs
    I am running a legacy XP app that I would like to move on a network share. It is very simple and works in theory but the server providing the share is based on Linux (cannot configure) and the software does not work correctly because it is programmed case-insensitively, it seems. After some research, network shares behave like the filesystem they use underneath. This is normal. Unfortunately I cannot fix the software myself. Is there any way to turn the case-sensitivity into case-insensitivity for a Windows network drive on the client side? I fould two approaches: First, something like icasefile (http://wnd.katei.fi/icasefile/) that wraps around the program and intercepts the file I/O. This is for UNIX only. Secondly, a proxy virtual file system (e. g. something using Dokan). Unfortunately I couldn't find any suitable fs, the only possibility would be to put a case-insensitive filesystem on an image file and put this on the share using for example lmdisk (http://www.ltr-data.se/opencode.html/#ImDisk). Do you have any better ideas?

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  • Why can I view my site over a 3G connection but not through my wifi?

    - by Jonathan
    So, I am sitting in my office with four computers on the same network and internet connection. Two of the computers can visit this particular website. Two of the computer get a message "Google Chrome could not find". I have tried FF and IE also with the same problem. I can view the site 90% of the time on two of the working computers although the site seems slow and sometimes I also get the same errors as the other two computers. I have flushed the DNS, reset the router, tested the site on other peoples computers with success. Is this likely to be a site issue, an ISP issue, a hosting issue? Any advice is greatly appreciated. Here is the ping from the working machine: C:\Users\Jon>ping www.balihaicruises.com Pinging www.balihaicruises.com [208.113.173.102] with 32 bytes of data: Reply from 208.113.173.102: bytes=32 time=331ms TTL=47 Reply from 208.113.173.102: bytes=32 time=327ms TTL=47 Reply from 208.113.173.102: bytes=32 time=326ms TTL=47 Reply from 208.113.173.102: bytes=32 time=329ms TTL=47 Ping statistics for 208.113.173.102: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 326ms, Maximum = 331ms, Average = 328ms Traceroute: Tracing route to www.balihaicruises.com [208.113.173.102] over a maximum of 30 hops: 1 1 ms 17 ms 3 ms 192.168.1.1 2 42 ms 37 ms 36 ms 180.254.224.1 3 39 ms 47 ms 40 ms 180.252.1.69 4 36 ms 616 ms 57 ms 61.94.115.221 5 84 ms 76 ms 80 ms 180.240.191.98 6 73 ms 80 ms 72 ms 180.240.191.97 7 157 ms 143 ms 116 ms 180.240.190.82 8 115 ms 113 ms 120 ms ae1-123.hkg11.ip4.tinet.net [183.182.80.93] 9 331 ms 332 ms 335 ms xe-3-2-1.was14.ip4.tinet.net [89.149.184.30] 10 327 ms 330 ms 331 ms internap-gw.ip4.tinet.net [77.67.69.254] 11 437 ms 415 ms 350 ms border10.pc2-bbnet2.wdc002.pnap.net [216.52.127.73] 12 322 ms 823 ms 398 ms dreamhost-2.border10.wdc002.pnap.net [216.52.125.74] 13 328 ms 336 ms 326 ms ip-208-113-156-4.dreamhost.com [208.113.156.4] 14 326 ms 328 ms 336 ms ip-208-113-156-14.dreamhost.com [208.113.156.14] 15 327 ms 331 ms 333 ms apache2-udder.crisp.dreamhost.com [208.113.173.102] And then for the machine that doesn't work: C:\Users\Microsoft>ping www.balihaicruises.com Ping request could not find host www.balihaicruises.com. Please check the name and try again. C:\Users\Microsoft>tracert www.balihaicruises.com Unable to resolve target system name www.balihaicruises.com.

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  • Alternative Methods of Sharing Folders in Windows?

    - by Blaenk
    Hey guys. I'm running Windows 7 and as of now I simply share folders as one usually does in Windows. I then have a MacBook with Leopard (Now Snow Leopard) which I use to connect to my computer to mount the shares by going to Finder, then CMD + K and typing smb://BlaenkPC (The name of my PC) into the address box. This consequently connects to my computer and mounts all of the shares. The problem is that sometimes, if for example I close my MacBook (Which makes it go to sleep) or sometimes even without doing that, the connection somehow drops. Sometimes I close the MacBook and upon re-opening it, everything still works; it's random. It still shows the computer as being connected, but it just shows 'loading' indefinitely. If I hit 'eject' with the intention of re-connecting to the computer, it disappears from the sidebar (The Computer Icon) in Finder, but I cannot re-connect. Activity Monitor (or ps aux, whichever) both show hung instances of umount; one for each share that was mounted. I cannot kill these processes with kill or killall (Yes, even with sudo, and sending signal -9). This has happened to me before, and here is another person who has experienced this. My question boils down to this: Is there an alternative method of sharing folders in Windows, that my Mac can read/understand, that is possibly more reliable and preferably just as fast? I usually use the mounted shares to watch television episodes off my computer, or movies, etc. (In other words, I open them in VLC and they automatically stream from my computer). As far as I can tell, this is a problem with the Samba protocol. I have heard of NFS, but I am not sure if I would have to re-format my drives, or what. I don't mind running a service or daemon to allow the sharing of the folders, I just want it to be done and hopefully in a better way than typical Windows shares through Samba. Usually when I encounter this problem, which is often (read: every day), I have no other option but to restart the MacBook. As I stated in the first question I linked to, shutting down and restarting don't work; I have to manually force the shutdown by holding the power button. I have not modified my installation of Mac OS X in any hackish way, so I doubt it's something with the Operating System, but worst come to worst, I might end up reformatting and doing a clean install to see if that fixes anything, as I am at a complete loss as to what may be causing the problem, and no one else seems to have any idea or care, despite there being quite a few people suffering from this problem, as my research has shown. Any pieces of information that can help are extremely appreciated. You don't have to answer every question on here, but maybe even some insight as to why it might not be possible to kill those hung umount instances for example, or why I may not be able to reconnect using samba (Is it something regarding the way the protocol works?). One thing to note is that I have another computer in the home network that doesn't seem to have this problem. However, it is also running Windows 7 (Note though that I am not using the homegroup feature, but the typical windows sharing feature). My only deduction is that the problem is being caused by the way the Mac (Or Samba implementation, whichever) is handling things. Perhaps it is a limitation.

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  • Long connection times from PHP to MySQL on EC2

    - by Erik Giberti
    I'm having an intermittent issue connecting to a database slave with InnoDB. Intermittently I get connections taking longer than 2 seconds. These servers are hosted on Amazon's EC2. The app server is PHP 5.2/Apache running on Ubuntu. The DB slave is running Percona's XtraDB 5.1 on Ubuntu 9.10. It's using an EBS Raid array for the data storage. We already use skip name resolve and bind to address 0.0.0.0. This is a stub of the PHP code that's failing $tmp = mysqli_init(); $start_time = microtime(true); $tmp-options(MYSQLI_OPT_CONNECT_TIMEOUT, 2); $tmp-real_connect($DB_SERVERS[$server]['server'], $DB_SERVERS[$server]['username'], $DB_SERVERS[$server]['password'], $DB_SERVERS[$server]['schema'], $DB_SERVERS[$server]['port']); if(mysqli_connect_errno()){ $timer = microtime(true) - $start_time; mail($errors_to,'DB connection error',$timer); } There's more than 300Mb available on the DB server for new connections and the server is nowhere near the max allowed (60 of 1,200). Loading on both servers is < 2 on 4 core m1.xlarge instances. Some highlights from the mysql config max_connections = 1200 thread_stack = 512K thread_cache_size = 1024 thread_concurrency = 16 innodb-file-per-table innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 13G Any help on tracing the source of the slowdown is appreciated. [EDIT] I have been updating the sysctl values for the network but they don't seem to be fixing the problem. I made the following adjustments on both the database and application servers. net.ipv4.tcp_window_scaling = 1 net.ipv4.tcp_sack = 0 net.ipv4.tcp_timestamps = 0 net.ipv4.tcp_fin_timeout = 20 net.ipv4.tcp_keepalive_time = 180 net.ipv4.tcp_max_syn_backlog = 1280 net.ipv4.tcp_synack_retries = 1 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 87380 16777216 [EDIT] Per jaimieb's suggestion, I added some tracing and captured the following data using time. This server handles about 51 queries/second at this the time of day. The connection error was raised once (at 13:06:36) during the 3 minute window outlined below. Since there was 1 failure and roughly 9,200 successful connections, I think this isn't going to produce anything meaningful in terms of reporting. Script: date /root/database_server.txt (time mysql -h database_Server -D schema_name -u appuser -p apppassword -e '') /dev/null 2 /root/database_server.txt Results: === Application Server 1 === Mon Feb 22 13:05:01 EST 2010 real 0m0.008s user 0m0.001s sys 0m0.000s Mon Feb 22 13:06:01 EST 2010 real 0m0.007s user 0m0.002s sys 0m0.000s Mon Feb 22 13:07:01 EST 2010 real 0m0.008s user 0m0.000s sys 0m0.001s === Application Server 2 === Mon Feb 22 13:05:01 EST 2010 real 0m0.009s user 0m0.000s sys 0m0.002s Mon Feb 22 13:06:01 EST 2010 real 0m0.009s user 0m0.001s sys 0m0.003s Mon Feb 22 13:07:01 EST 2010 real 0m0.008s user 0m0.000s sys 0m0.001s === Database Server === Mon Feb 22 13:05:01 EST 2010 real 0m0.016s user 0m0.000s sys 0m0.010s Mon Feb 22 13:06:01 EST 2010 real 0m0.006s user 0m0.010s sys 0m0.000s Mon Feb 22 13:07:01 EST 2010 real 0m0.016s user 0m0.000s sys 0m0.010s [EDIT] Per a suggestion received on a LinkedIn question, I tried setting the back_log value higher. We had been running the default value (50) and increased it to 150. We also raised the kernel value /proc/sys/net/core/somaxconn (maximum socket connections) to 256 on both the application and database server from the default 128. We did see some elevation in processor utilization as a result but still received connection timeouts.

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