Member Avatar for rockjock

Our main server is running Windows 2000 adv server and basically running as a local file server, terminal server and application server.
We have two other company branches in other parts of the country connecting via VPN (terminal services)to our main server using an accounting package developed for our needs.

The main server has two network cards on the same network. This makes it appear that there are two servers on the network with the same name. This is NOT correct. It was done to address the speed problem with terminal server sessions. It appears to work most of the time. When the routing gets "confused" the terminal server sessions will come to a grinding halt that will need the servers to be restarted to rectify the problems.
This issue is the main contributor to errors being logged by the servers in their respective event viewers informing us about one network adapter that keeps disconnecting and then reconnecting.
We are running accounting applications and when this happens the program crashes.

Is there a way to streamline this process and keep the network adapter from disconnections?

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Short summary and practical plan.

Having two NICs on the same IP network creates name-resolution and routing ambiguity: Windows can register both addresses for the same computer name (DNS/WINS/NetBIOS) and the TCP/IP stack will sometimes use the “other” interface for replies, producing asymmetric routing and the session stalls you see. (cnblogs.com)

Quick checks (fast to do)

  • Confirm whether the same adapter is the one that drops (as suggested). Note the adapter name, driver version and event-log timestamps.
  • Swap the cable and switch port and update/reinstall the NIC driver (as advised) to rule out physical or driver flakiness.
  • Capture the moment with ipconfig /all, route print and the System/Event logs so you can correlate adapter disconnects with routing changes.

Config changes that often stop the problem (non‑disruptive)

  • Stop the server advertising two addresses for the same name: disable dynamic DNS registration on the secondary adapter and disable NetBIOS over TCP/IP for that adapter so only the primary address is published. (learn.microsoft.com)
  • Remove any default gateway from the secondary NIC; add static routes or set a manual interface metric so outbound traffic uses the intended interface (Windows will otherwise pick routes based on interface metrics/binding order). (learn.microsoft.com)

If performance or link flaps continue

  • Check switch-port counters (CRC/FCS, collisions) and fix any speed/duplex mismatches; autonegotiation failures are a common cause of intermittent drops under load. (cisco.com)
  • For real bandwidth and failover without the naming/routing problems, use vendor-supported NIC teaming or 802.3ad (LACP) with switch support—Windows 2000 requires the vendor teaming utility (Intel ANS, Broadcom tools, etc.). (cs.uwaterloo.ca)

Short test plan: isolate (disable the secondary NIC) → verify stability → reintroduce changes one at a time (disable DNS/NetBIOS, remove gateway, set metric) → monitor. If stability returns, implement teaming or separate the traffic onto VLANs/sublinks as a long‑term fix.

Commands to run while troubleshooting:

ipconfig /all
route print
ipconfig /registerdns
route add <network> mask <mask> <gateway> -p

Recommended Answers

All 6 Replies

Member Avatar for DenisOxon

Can you split the network into two physical networks, with terminal servers on one and rest of users on other. Then connect one network card to one and other to other network.

Member Avatar for Spriggan

yup, looks like you need another segment, and maybe some good QoS software.

Member Avatar for DenisOxon

Hi agin,

I have just reread your post - is it always same network card that is disconnecting ?

If so please check there is no ip number clash. If not the card might be failing and need replacing.

Member Avatar for rockjock

It's the same card that disconnects, the cards have seperate IP addresses .1 and .2.
They will most likely have to be seperated at some point due to increase in strain placed on our main server.

Member Avatar for DenisOxon

Hi

Do the ip numbers clash with other equipment on network ?

I feel one of the cards has a fault and I would replace the one that keeps going down. See if problem goes away.

Member Avatar for Spriggan

but first, replace the drivers, you never know...

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