home lan problems: frequent disconnects

[ccrb]

I have a half dozen PCs connected to Dlink DSS8+ switch and a Dlink DI804 router, to a cable modem, Brighthouse roadrunner Internet.

My primary computer that I use for email and most surfing and ftping, has had problems with frequent disconnects/reconnects. This manifests itself in ftp (interuption, cancel) and in Mirc. It's less obvious in IE because IE retries or just appears to hang and works fine with a refresh.

The NIC is a DLink run of the mill NIC. The computer is an AMD Athlon, Asus Mother Board, running Win2000 Pro. For e-mail I use Eudora paid version 4.3. I installed IIS, but usually have it shut down. All system patches are up to date.

I have replaced the NIC, the computer and the OS. This was a clean install of W2000, not an upgrade.

Other computers on the LAN do not have this interrupt problem... meaning ... if i have a large file or a large number of files to ftp, I'd be smart to use a nearby computer instead of the problem one.

I've been through testing with Dlink. They were no help.

the disconnect/reconnect is so fast, it doesn't appear to be detectable with a looping ping. I can't say for sure if I'm disconnecting only from the Internet or also from the LAN.

I mentioned Eudora because it also times out a lot on its connections.

I was running zonealarm free, but removing it didn't solve the issue. Running with Eudora off still sees some occurances, although fewer and less often. I'm wondering if it's load related.

Any ideas?

 

[John Lewis]

Could be a lot of things, but you haven't detailed your hardware check. If you haven't already done so, try a different cable, a different port on the switch.

I don't see anything that should be a load problem. One thing that I can think of . . . you mentioned ftp. If you are uploading file frequently and you have a asymetrical connection (cable almost always is), you could be flooding your upstream bandwidth, which would produce the what you are describing. Same would apply if others were downloading from your computer.

 

[ccrb]

I have replaced the cable, the NIC, the computer itself, and tried different ports on the router. The only thing in common is the cable service... and my list of applications I am running.

I have several computers but the problem only seems to manifest itself with this one. And frankly, I'm not sure if the disconnect is between my nic and the router, or beyond the router in the session to my isp. For example, when I get a disconnect with ftp or irc, I don't know if I'm disconnected from my peers on the LAN. The fact that other computers don't *seem* to have this problem leads me to wonder if it's a application load problem... when the machine is idle (when I turn off eudora and there's no more polling -- I poll about 15 pop3 mailboxes) it seems to be less frequent.

It would be really nice if there was a network diagnostic tool. Pings are too instantaneous.

the messages in ftp and irc are basic "connection reset" messages... not terribly helpful

The cable company has been no help to me, as they want me to remove the switch and router from the picture and direct connect only... something I don't really have the luxury of.

 

[ccrb]

and if it's a flooding issue because of an asynchronous connect for the cable modem... uploads are throttled at a lower speed than downloads... what is the solution? Is there some sort of flow control available?

 

[bcastner]

It is your NIC.

See these sites for possible workarounds:

http://homepage.ntlworld.com/j.buchanan/winmx/faq-restart.html

http://www.dessent.net/btfaq/#freeze