Re: What's up with my network???

"User" <[email protected]> wrote in message 
news:[email protected]...
>> Windows SBS 2003 Server
>> Cisco Pix 5??
>> Headaches up to here...

Your description sounds like a common problem they were having back in 
2002-2003 with Macs... whenever a Mac's NIC was put into promiscuous mode 
with the firewall turned on, it would send RSTs for ALL traffic it saw, 
whether that traffic was destined for the Mac or not. They found this bug 
at a conference, where a laptop was in promiscuous mode, and everyone else 
on the WiFi connection kept getting page load problems when surfing. This 
was on a wireless network (which by necessity operates as a hub)... if 
your computers are on a switch, you shouldn't be seeing this particular 
problem, since a switch segregates the traffic (although I suppose if you 
have a wireless AP that is forwarding all packets from the wired and 
wireless network, it might happen (i.e.: you plugged your wireless AP into 
a hub in parallel with your switch, so the AP is seeing all packets)).

ROUTER
    ||
  HUB
  ||    ||
AP   SWITCH
  ||              ||
  ||              WIRED
  WIRELESS

Do you have any Macs on your network, and are your machines on a hub, or 
some of them connected wirelessly? If so, try taking them off the network 
to see if your problem goes away.

Other than that, I'd suggest disconnecting one machine at a time, to see 
if the problem goes away... when it does, troubleshoot the problem machine 
by sniffing packets.

It sounds like either you're getting connection resets from somewhere (as 
described above), your DNS cache is corrupted or the DNS server is 
otherwise malfunctioning, or you're somehow running out of TTL hops (check 
the TTL settings on your machines).

Why are you using a Microsoft DNS server? It'd be much easier (and have 
higher performance) if you ran SimpleDNS+ as your DNS server. I've run it 
for years, and it's rock stable... and it can handle an ungodly high 
number of requests per second (i.e.: I've tried to DoS my DNS server, and 
couldn't). Plus, it's easy to set up... much easier than any Microsoft DNS 
server. And I've never experienced any DNS cache corruption problems 
(which is another scenario you should look at in troubleshooting).