Network Connection

By afeer ยท 16 replies
May 31, 2008
  1. I M Using Win XP in a N/W environment. Sometimes it stops communicating ANY FEW systems in my network. After repairing the n/w card it works normally. It may happen once a day or even 10 times a day. Any solution ?
  2. jobeard

    jobeard TS Ambassador Posts: 11,128   +982

    hint: write words to be sure you are understood -- N/W?? guess you're saying
    "in a networked environment" you lose your connection.

    If so, first update the modem/router firmware and then the wifi or ethernet drivers.
  3. raybay

    raybay TS Evangelist Posts: 7,241   +10

    In addition to N/W, please tell us what you mean by "ANY FEW systems"? and "after repairing the n/w" How are you "repairing" it.
  4. afeer

    afeer TS Rookie Topic Starter

    thnx for reply, wel u r right it's network environment second i repair the network card by just right click, repair method. wel i have approx 200 computer in network staring from 1 to 200. for example, computer 10 stops communicating computer 20, 21, 60 and at the same time it communicates with others on the same LAN on the same switch. also at the same time, computer 20 , 21 and 60 communicate, with all computers. as we are using application its session stops which creates situation.

    waiting for response
  5. matav

    matav TS Enthusiast Posts: 144

    you still aren't clear
    so what did you mean there?
    anyways, lets start from basic
    Check cable condition and for any loose contacts esp. at the switch side.
    How many switches have been implemeted? does one entire switch segment get disconnected from server side? Did you check the switch for errors?
    also measure the total length of the cable from this computer to the server, cauz the signal strength may be dying by the time it reaches server.
    The computers on same switch can communicate with each other but not others computers on the entire network...
    This clearly shows that the switch is losing connection to the server.
    So check the switch for loose contacts.
    ... but still you confused by saying this:
    please explain the issue you are facing with better english and more details.
  6. kimsland

    kimsland Ex-TechSpotter Posts: 14,523

    Thanks matav

    I would also recommend clear proper English

    I found it hard to read (and understand), and I don't think anyone should assume what afeer means, with approx 200 computer (I mean ~200 computers)
  7. pyromaster114

    pyromaster114 TS Guru Posts: 246

    I guess, from your cruddy English, that you are having a problem where one computer (let's call it compA) is failing after a while to communicate with some (not necessarily all) other computers on the network.

    One thing to check is your Windows XP Firewall. I usually leave the Windows Firewall turned off and rely on my router firewall and other 3rd party firewalls (Peer Guardian is nice...) to keep out things I don't want coming in.

    Next, check that all your drivers are up to date, and use static IPs where possible, this can help ensure that you don't have a DHCP related problem.

    Also, could you tell us what type of router you are using?
    I recommend that you use a Linksys router, as they seem to be the best usually, however if you can't afford one, we'll have to make do with what you have if possible.

    Update your router's firmware (from the manufacturer's website).
    Update your Network Interface Card drivers.
    Ensure that there is nothing obstructing any wireless connections (large steel walls, large concrete walls, etc. usually don't help with having a reliable connection.).

    From what you're saying, it's either a firewall based problem or a DHCP problem...
    but you didn't say all that much... so I don't know.
  8. jobeard

    jobeard TS Ambassador Posts: 11,128   +982

    help yourself by making sure each and every system on the network is configured to use DHCP and not static ip addresses!

    sounds to me like you have conflicting IP addresses.

    There's only one good reason to use static ip addresses: that system is a server
    that all the others need to be able to connect to.

    If you need fixed (static) addresses, this should be done on the Domain Controller for
    your network where your internal DHCP service forces IP addresss and keeps your
    internal DNS updated with the servier-name-->fixed.assigned.ip.address
  9. pyromaster114

    pyromaster114 TS Guru Posts: 246

    If you're using a Linksys or similar home router, some tend to have problems with their integrated DHCP server, so I was suggesting that you assign systems IP addresses OUTSIDE the DHCP range (check this in your router's configuration, usually above 150 or below 100).

    I know that using DHCP simplifies things, and it is usually better to do so.
    However, assuming your not going to have a DNS server for your house or anything, setting static IPs on your systems outside the DHCP range might not be a bad idea.
  10. tipstir

    tipstir TS Ambassador Posts: 2,473   +126

    I take it you have 200 nodes and you should have matching incoming jacks to patch panel connected 4x 48-port and 1x 24-port Cisco Catalyst switches connected to Cisco router for this infrastructure all running XP Pro correct? Or you have a off the shelf router and a few off the shelf switches.

    Running real server or PC acting as server using Windows Server 2000 or 2003?

    Need more details on your network... We're all network engineers, network technician some have all the certs you can name under the sun. Still all is good. Very knowledgeable members here.
  11. pyromaster114

    pyromaster114 TS Guru Posts: 246

    H01y 5h*t.... I missed the 200 computers part...
    If you really have that many computers... I hope that you are not running on off-the-shelf equipment...

    Forget what I said about not using DHCP... that's not good if you have that many unless you need them all to be always at the same IP address (for server type applications).
    If you really have that many, you should have a domain server... and I would try and have a DHCP server active for all that don't need static IPs...

    In any case, it still sounds like a firewall or IP problem.

    If you have a domain server, it may be a permission problem on there, since you say that session changes (log on/ log off) seem to cause this... hope this helps.
  12. afeer

    afeer TS Rookie Topic Starter

    thanks for the replies.
    let me clear you all guys about my network infrastructure.
    1. it's Intranet of more than 200 Computers.
    2. Main Gateway is Cisco 7206 Series Router
    3. DHCP and Static addresses both are used but different ranges.
    4. Network Cables are fine within the recommended range of lenght.
    5. face plates are fine and even signal strength is very good
    6. NO interference in wireless checked that as well.
    7. Cisco Switches are used and configured in proper VLAN environment.
    8. Drivers of network cards anupdated
    9. IOS is updated.

    Every thing was working fine, until this situation comes. If a system communicate fine with my gateway and switches and even about 50 computers on the network perfectly, why it stops communicating with rest of computers in the network. when i repair the network card in windows, it at once starts working normally. after some time the same computer again stops communicating. this situation may occur once in a day or any number of times in a day.
  13. tipstir

    tipstir TS Ambassador Posts: 2,473   +126

    Good we're getting some where now... So what's did you change on those 50 lately? Did you upgrade the Service Pack on them to 3? What changed? Also when last then you refresh or restart the server, the router and the switches? Did you flash the firmware on the Cisco switches or the router with the most current one?

    Something changed in those 50 systems you have on the network domain?

    VLAN are the ports set to auto or 10 or 100 or 1000? Every system have to be set the same way. We found at our shop. All VLAN ports are set to Auto and same for the desktops and laptops which connect to them are auto. We're in the process doing a network refresh to Gig domain for users. Change out switches to 3750. Just finished VLAN1 Project elimination finding 5,500 rouge nodes on the network was a real pain. Some couldn't be telnet into. Do you have some sort of rake program to tell you daily what's connected to switches. Like a report we call it Net Rake! I also use a snort of sniffer, well I could use anything I want to get the job done. LAN-Spy works great on domains when I did SP2 roll out just scan the systems computer names to see which system got the new package over domain and which one had to be re-pushed over AD..
  14. raybay

    raybay TS Evangelist Posts: 7,241   +10

    Check your cables very carefully, particularly if hand-crimped on site, purchased on a "deal" to save money, or installed by a contractor. We see cables and connectors as the problem way too often on large systems.
  15. NetCablesPlus

    NetCablesPlus TS Maniac Posts: 228

    Raybay is absolutely correct. It never fails to amaze me that organizations will spenf significant money on their hardware and then use hand-crimped cables to connect them. The cost of factory manufactured and tested patch cables is so low these days, that it simply makes no sense to risk the results of a poorly crimped cable.
  16. tipstir

    tipstir TS Ambassador Posts: 2,473   +126

    Patch cables don't fail as much as the ports in the switches, but let's see if the user changed something recently? Maybe update patches or something else. What I forgot to mention that we have some issues with is heat. But these switches and routers do go down. Could be something wrong with the switch that these 48 are on?
  17. afeer

    afeer TS Rookie Topic Starter

    HI all and thanks for replies,

    Problem is solved. the actual cause and culprit is my DSL / Wireless Modem / Router. It's name is Zyxel a chines device. It's firmware starts malfunctioning and causing strange issues in the network. The latest issue i faced a day before yesterday was IP conflict. I then searched that who has given the IP of my Proxy / Switch and systems. After thorough troubleshooting I found that culprit in my Server Room. It was ZyXel. when i disconnect the device from the network, everything starts working normally.

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