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  • No internet on some devices, still on WiFi

    - by Joost
    Ok, here's the situation. I live with 3 friends, and we often sit in the living room with laptops out. There's a WiFi router in the kitchen, and we have quite a stable connection. The issue, however, is this: sometimes, all of a sudden one of my friends loses internet connection. Even disconnecting/reconnecting to the WiFi network does not help. When we restart the router, though, it works like a charm again. The odd thing is, it happens just for this one Windows 7 laptop. We've switched routers (for a different reason) in the mean time, but the issue remained. This makes me suspect the laptop even more. I realise I've given little details, but I don't really know what to try/do. Any suggestions what it might be?

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  • WNDR3700 Router + Cisco SG200-08 + LACP + Dual Uplink

    - by kobaltz
    Background I have a storage server that has several virtual machine images stored on them. I would store them locally, but I have limited space on my desktop (using SSD storage). I would like to increase the bandwidth between the desktop and the storage server by using two NICs on each computer. My original configuration allowed about 55MBps between the desktop and storage server. This storage server also has several TBs of documents, pictures, movies, vms, and ISO/programs. The storage server has 8 1.5TB hard drives in a RAID 10 configuration with a hardware RAID controller. The benchmarks on the RAID 10 are about 300MBps. Configuration In short, I am trying to bridge my switch and router. The switch is a small 8 port Cisco smart switch that supports 802.3ad LACP. I have two computers plugged into the switch, each with 2 Intel Gigabit NICs. The first computer is a Windows 7 machine that has the Intel ANS software installed. I have LACP configured with the computer and now show 3 NICs (2 Physical + 1 TEAM Virtual @ 2Gbps). It looks like this computer is configured correctly. I trunked the two ports that this computer is plugged into with the switch's web interface. The second computer is a homebrew storage box running debian. I also have the bonding enabled on this machine and the switch configured with LACP. Without having the WNDR3700 router in the picture yet, I am able to communicate between the Windows 7 machine and the debian box since they both have static IP addresses. With LACP enabled on both machines I am getting about 106-108MBps speeds. Issue I plug in a network cable from the switch into the router and enable DHCP on the desktop. I saw no need to have a static address on the desktop. My transfer rates are still from 106MBps-108MBps. While this is still a boost, I am trying to figure out how to get about 140-180MBps. I am thinking that I need to increase the bandwidth from the router to the switch. My switch allows 4 groups for port trunking. I plugged in a second network cable from the router to the switch. My question is, what is the proper way to fix this issue. Should I port trunk the two ports that are going from the switch to the router? Keep in mind that the router is a WNDR3700 and is unsure whether or not it supports LACP. I do have OpenWRT installed on the router, but it still wasn't clear in any documentation that I found if it supported 802.3ad LACP standards. I am also wondering if there needs to be anything changed within the Cisco settings. [Edit] - Corrected some numbers, wasn't really paying attention. It looks like the speeds though at least two NICs are bonded with LACP is still reaching the max bandwidth of one port. Is there a way to configure the switch so that I can increase this bandwidth? Also, on the storage server, I had a couple of extra NICs laying around and threw them on there as well. Another EDIT and More Findings I happened to look at the traffic of each individual NIC and think that I see the problem. I tested with a simple transfer for a 4GB file. I noticed that only one of the NICs was taking the load of the traffic. I then copied the file back to the Storage Server and noticed that the other NIC was sending out the traffic. I have 802.3ad LACP enabled on the two NICs and I see that it gets enabled dynamically on the switch's interface. Should I be using Static Link Aggregation?

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  • Customer site is out of IP addresses, they want to go from /24 to /12 netmask... Bad idea?

    - by ewwhite
    One of my client sites called to ask me to change the subnet masks of the Linux servers I manage there while they re-IP/change the netmask of their network based on a 10.0.0.x scheme. "Can you change the server netmasks from 255.255.255.0 to 255.240.0.0?" You mean, 255.255.240.0? "No, 255.240.0.0." Are you sure you need that many IP addresses? "Yeah, we never want to run out of IP addresses." A quick check against the Subnet Cheat Sheet shows: a 255.255.255.0 netmask, a /24 provides 256 hosts. It's clear to see that an organization can exhaust that number of IP addresses. a 255.240.0.0 netmask, a /12 provides 1,048,576 hosts. This is a small < 200-user site. I doubt that they'd allocate more than 400 IP addresses. I suggested something that provides fewer hosts, like a /22 or /21 (1024 and 2048 hosts, respectively), but was unable to give a specific reason against using the /12 subnet. Is there anything this customer should be concerned about? Are there any specific reasons they shouldn't use such an incredibly large mask in their environment?

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  • How frequent are network partitions on cloud services?

    - by roja
    Much is made of the CAP trade-off for data storage where conflicts can be introduced if there is a network partition. My question is there any evidence that this is a problem that arises with any significant frequency in modern cloud IAAS services e.g.; EC2, Azure, Rackspace. Is it a problem which, despite being a theoretical roadblock in constructing idealised distributed systems is, in fact, a non-issue for all practical concerns? Has anyone experienced a network partition within one of these systems (within a single data-centre?) If so would you be willing to share any details?

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  • Problem connecting to Ubuntu Server in same local network.

    - by frbry
    I have my LAN set up as below: 192.168.2.1: ADSL Router (DHCP Range: 192.168.2.2-192.168.2.250) 192.168.2.254: Wireless Access Point 192.168.2.253: Ubuntu Server (Static IP) 192.168.2.2: My Laptop (Connects to Internet via the Wireless AP) NAT in router is active and set up to transfer requests made over port 80 to 192.168.2.253. Router's firewall is inactive. No IPs in DMZ. My friends get Apache's It Works page when they try to enter http://my_external_ip. But I get Router's configuration page instead of that. What should I check or do? Thanks.

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  • Network load balancing, efficience and limits?

    - by Vimvq1987
    I'm about to study about NLB on Windows Server 2003. It archives both of my interests now: scalability and high-availability. But I don't know about its power in production environment. Is NLB a efficient solution? How does it implement in real-world? Is it popular? What are its limit? Thank you so much for answering my questions. :)

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  • default virtual network interface

    - by Zulakis
    I got a single ethernet connection to a network but need multiple ips. Because of this, I am using virtual network interfaces like this: auto intern iface intern inet static address ... netmask ... gateway ...U auto intern:1 iface intern:1 inet static address ... netmask ... gateway ... I need to specify which IP should be used by default for outgoing traffic. How can I do that?

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  • retransmission of lost TCP segment

    - by tcpip
    What will happen in the following scenario (assume the connection is already established): (stack A) send 10 byte data (stack B) send ACK for 10 byte data (stack B) send 200 byte data (stack B) send 100 byte data (stack B) send 50 byte data (stack A) send ACK for 350 byte data and also send 70 bytes data This segment gets lost and does not reach machine B. (stack B) retransmit 200 byte data (step 3) (stack A) send ACK for 200 byte data and the next expected seq number as the one for 70 bytes data Question: Should 70 bytes data be also transferred with the ACK in step 8? Note that the retransmission timer for step 6 has not expired yet.

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  • Mass Port Forwarding?

    - by Devoted
    Hi I had trouble but I finally port forwarded 21-23 and thus got SSH working on my Ubuntu machine. If I want to do other things with it such as FTP, should I just port forward 1-10000 so I don't have to worry about port forwarding each individual port? What are the advantages/disadvantages of this?

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  • Using PVLANs with normal VLANs in a trunked environment

    - by user974896
    Assume a trunked environment with two switches, S1 and S2. The swtiches are connected with a trunk port designed to pass VLAN 26. What would happen if VLAN 26 on S2 is configured as a private-vlan with the default gateway and DHCP server and default gateway as promisc ports. What if S1's VLAN 26 is configured as a standard VLAN. Would the hosts on S1 be able to communicate with the promisc ports on S2? Would they be able to communicate with the hosts on S2? To further complicate things what if the DHCP server were to reside on S1 and I wanted S2 to have private VLANS with promisc ports as the gateway and DHCP server while still leaving S1 in a standard vlan configuration.

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  • How to build a private Wi-Fi Network server with VMware?

    - by Maarten Schermer
    For a school project, we have to build a Private network with VMware vSphere , which we can connect to with a Username and Password. On the network we want to create a folder for each Useraccount. Also we must have add a few groups (Admin,Customer,Manager). We must be able to connect to our network via the school Wi-Fi. We want to build a safe and secure network, with an easy way to access the network. Do you have any tips on how to approach this?

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  • Is there a utility to visualise / isolate and watch application calls

    - by MyStream
    Note: I'm not sure what to search for so guidance on that may be just as valuable as an answer. I'm looking for a way to visually compare activity of two applications (in this case a webserver with php communicating with the system or mysql or network devices, etc) such that I can compare the performance at a glance. I know there are tools to generate data dumps from benchmarks for apache and some available for php for tracing that you can dump and analyse but what I'm looking for is something that can report performance metrics visually from data on calls (what called what, how long did it take, how much memory did it consume, how can that be represented visually in a call stack) and present it graphically as if it were a topology or layered visual with different elements of system calls occupying different layers. A typical visual may consist of (e.g. using swim diagrams as just one analogy): Network (details here relevant to network diagnostics) | ^ back out v | Linux (details here related to firewall/routing diagnostics) ^ back to network | | V ^ back to system Apache (details here related to web request) | | ^ response to V | apache PHP (etc) PHP---------->other accesses to php files/resources----- | ^ v | MySQL (total time) MySQL | ^ V | Each call listed + time + tables hit/record returned My aim would be to be able to 'inspect' a request/range of requests over a period of time to see what constituted the activity at that point in time and trace it from beginning to end as a diagnostic tool. Is there any such work in this direction? I realise it would be intensive on the server, but the intention is to benchmark and analyse processes against each other for both educational and professional reasons and a visual aid is a great eye-opener compared to raw statistics or dozens of discrete activity vs time graphs. It's hard to show the full cycle. Any pointers welcome. Thanks! FROM COMMENTS: > XHProf in conjunction with other programs such as Perconna toolkit > (percona.com/doc/percona-toolkit/2.0/pt-pmp.html) for mySQL run apache > with httpd -X & (Single threaded debug mode and background) then > attach with strace -> kcache grind

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  • How can I join two simple home networks together using an ethernet cable?

    - by Ilia Jerebtsov
    I want to join two different home networks together like so: PC A1 PC A2 PC B1 PC B2 \ / \ / Gateway A <----- ethr. cable -----> Gateway B | | ADSL modem A ADSL modem B Both networks are of the basic residential type with identical configuration, with all PCs running Vista/7. The point is to temporarily join two apartments in a building for gaming and file sharing, and the holy grail would be: PCs on network A can access PCs on network B and vice-versa (file shares and gaming). Each network uses its own internet connection. Data between networks shouldn't take a trip through the internet (broadband upload speeds are severely capped) A network's internet access should continue working if the joining cable is disconnected with minimal configuration changes. How closely can this be achieved?

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  • convert home phone wiring to Ethernet

    - by aaa
    can i convert phone wiring in walls to act as only Ethernet network cause the phone wiring is not in use and not connected to the phone company so there is no voltage in the wires i remove the wall plate and i find 6 wires blue,blue/white,green,green/white,orange,orange/white , and i know that Ethernet use 8 here is what i am thinking get Ethernet cable cut it in half and attach wires from wall to the first computer and the same with the other computer so if this is possible do i just attach wires in the same color and ignore brown wire or do i have to rearrange wires , and how much the speed will be thank you in advance

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  • xen + debian network after upgrade squeeze to wheeze

    - by rush
    I've got a Debian + Xen server. After a system upgrade to the stable version the network doesn't come up after boot. Every time after reboot I need to bring it up manually. The network configuration was not changed during upgrade. Here is /etc/network/interfaces: auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 11.22.33.44 netmask 255.255.255.0 gateway 11.22.33.1 nameserver 8.8.8.8 After boot ip r shows no route and eth0 has no ip address. Manually ip and route setup goes fine and network starts working. Messages from dmesg about network I've found (looks like nothing interesting) [ 3.894401] ACPI: Fan [FAN3] (off) [ 3.894444] ACPI: Fan [FAN4] (off) [ 4.178348] e1000e 0000:00:19.0: eth0: (PCI Express:2.5GT/s:Width x1) 00:1e:67:14:66:c9 [ 4.178351] e1000e 0000:00:19.0: eth0: Intel(R) PRO/1000 Network Connection [ 4.178392] e1000e 0000:00:19.0: eth0: MAC: 10, PHY: 11, PBA No: 0100FF-0FF [ 4.178413] e1000e 0000:02:00.0: Disabling ASPM L0s L1 [ 4.178432] xen: registering gsi 16 triggering 0 polarity 1 -- [ 4.223667] ata5: DUMMY [ 4.223668] ata6: DUMMY [ 4.289153] e1000e 0000:02:00.0: eth1: (PCI Express:2.5GT/s:Width x1) 00:1e:67:14:66:c8 [ 4.289155] e1000e 0000:02:00.0: eth1: Intel(R) PRO/1000 Network Connection [ 4.289245] e1000e 0000:02:00.0: eth1: MAC: 3, PHY: 8, PBA No: 1000FF-0FF [ 4.506908] usb 1-1: new high-speed USB device number 2 using ehci_hcd [ 4.542920] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300) -- [ 10.362999] EXT4-fs (dm-23): mounted filesystem with ordered data mode. Opts: (null) [ 10.419103] EXT4-fs (dm-3): mounted filesystem with ordered data mode. Opts: (null) [ 10.988255] ADDRCONF(NETDEV_UP): eth1: link is not ready [ 13.175533] Event-channel device installed. [ 13.287555] XENBUS: Unable to read cpu state -- [ 13.288670] XENBUS: Unable to read cpu state [ 13.965939] Bridge firewalling registered [ 14.134048] e1000e: eth1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx [ 14.283862] ADDRCONF(NETDEV_UP): peth0: link is not ready [ 14.284543] ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready [ 17.800627] e1000e: peth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx [ 17.801377] ADDRCONF(NETDEV_CHANGE): peth0: link becomes ready [ 18.307278] device peth0 entered promiscuous mode [ 24.538899] eth1: no IPv6 routers present [ 28.570902] peth0: no IPv6 routers present I've upgraded two servers and I've such behaviour on two of them. How to fix this and get network starts automatically on boot?

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  • How to use aliases for remote hosts when accessing locally

    - by alexloh
    I would like to use an alias for a remote host. For example, when instead of "ping giraffe.foo.bar.com" I want to do "ping giraffe", but only when I do it from my own machine. I am able to do this for raw IP addresses by adding an entry in /etc/hosts (ie "123.456.1.0 giraffe"), but it does not seem to work for host names.

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  • Internet setup for my office

    - by prakash
    We have two internet connections to our office and our current setup is like this.. The internet connections require pppoe log in so i take each cable and plug it into a wifi router and configure the router to log in to the pppoe and then plug in a cable from the router to a switch and distribute the internet throughout my office. The problem with this setup is it is really hard to monitor and im not able to monitor who is hogging internet usage and what he or she is actually using it for. apart from this we also have a nas setup which is routed through another switch . Could someone please throw a little light on how i can restructure this setup for easy monitoring and better transparency... ? each wan router is connected to a different switch and is distributed to users accordingly.. we have around 40 users in the office.. we want to setup a single linux box to which i want to connect the two wan connections and from there distribute it to all our users.... im looking for a solution where we do not have to invest more that buying a single pc and a couple of nics

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  • What software is available to keep track of hundreds of servers?

    - by djangofan
    What good software is available (free or not free) to help me keep track of information relating to hundreds of servers, their relationships to each other (parent/child, category, type), and information on connecting to them, as well as possibly showing a picture or grid of some kind that allows me to report these relationships and key information to my supervisor. I am trying to avoid the "spreadsheet solution" or "visio solution" because I want to share this information and make changes with other persons in my server team. In other words, the solution I am looking for is a cross between a spreadsheet solution and a visio solution, providing both graphing and configuration information WITHOUT monitoring, and in a consistent format.

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  • How to get all IPs of a domain?

    - by DenMark
    How can I get all IPs of a domain name, say, www.google.com? Of course, nslookup and host command will give me IPs of a domain. But what shall I do if I want a list ALL (or, at least a lot more than just one or two..) IPs of that domain?

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  • Why Would one VLAN have no Communication on one Switch?

    - by Webs
    So the problem is we have a device or host that needs to communicate on a specific VLAN. This VLAN is not new, it is running all throughout our environment and works fine. But the VLAN was recently configured on the switch in question, a Cisco 3750. The DHCP server is handing out addresses on that VLAN with no problem. I have verified the cable between the host and switch and tried multiple hosts, but none of them can communicate or get an address. I plugged my laptop into an empty port which had a different VLAN assigned and immediately got a DHCP address. When I changed that port to the same VLAN I'm having issues with I got the same problem. The laptop just sits there and tries to DHCP an address but nothing happens. I double checked the cores and their Layer 3 VLAN config and its fine too. Plus I figured the issue couldn't be with them because the VLAN works fine everywhere else it exists. So the only other thing I can think of is the switch, but the VLAN exists on the switch and seems to be configured correctly. The trunks appear to be configured just fine as well too. Anyone have any ideas? I'm lost on this one.

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  • What is causing my internet to be slow on one laptop but not the other and only at a distance?

    - by Matt Case
    I have a newer laptop, purchased within the last year (acer aspire 7740). This laptop does not have any problem connecting to wireless networks and indicates that the signal strength is excellent on most of the wireless networks I connect to. When the laptop is within 10 feet of my wireless router it gets 30 down 10 up. When it is farther away than 10 feet it will be lucky to get 3 down and 1 up. I also have an older laptop, purchased in 2005, that has no problems at all at the same range. None of my phones, gaming consoles or tablets have this problem. I am beginning to think that the problem must be some hardware defect with the wireless card. I can provide additional information if needed. Just thought I'd check to see what others thought because I've been working on computers my whole life and have never heard of this happening. I have also tried to change the channels on my wireless router and have had no success with this idea.

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  • How to use a Network adapter only for a specific Connection on Win7?

    - by Tokk
    Hey, Guys I've got several network adapter in my PC (from LAN, WLAN, VPN etc...) and what I want to accomplish is that some specific adresses use the VPN adapter, while all others use eiter LAN or WLAN. (So for example http://win-server/ is using VPN, while www.google still uses LAN connection.) I've want to solve this with the Windows settings and not the VPN settings to make sure I can do it with every VPN-Provider. Thank You

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  • Connecting office to data center via Metro-ethernet

    - by Eric
    I am installing a metro ethernet link from my office to my data center. The office will have a cisco 3750 with several vlans. The data center end will have a more complicated set up. The metro e from the office will connect to a 2960, which will have two other 2960s with a few vlans and a 2811 router connected to it for connectivity to our other environments and the internet. I am looking at implementing this by connecting the office 3750 and the data center 2960 with a dot1q trunk and doing all routing at the 2811. I will configure subinterfaces for gateways for each of the vlans on the 2811. I work for a small company and don't have much of a budget for an ideal architecture. I can post a simple diagram if needed for clarification. Is there anything I am missing here? I feel like I am forgetting something very basic and want to make sure I eliminate any boneheaded mistakes.

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