Heavy Network Traffic

I am trying to troubleshoot some Heavy Network Traffic issues that are
causing my 3Com switches to fail. I have narrowed the issue down to traffic
coming from my switch that all my servers are plugged in to.

I have (8) 2003 servers plugged into a single (Unfortunately Unmanaged) 3Com
switch. That switch uplinks to another 3Com switch which uplinks to the next
and so on. There are a total of 5 switches all being up linked. I have
checked and rechecked the uplinks and I do not have any loops or double
uplinks.

The issue that I am experiencing is every port on every switch is constantly
being hammered. All ports never stop blinking. If I disconnect the uplink
from the server switch the rest of the switches calm down.

I have two 2003 DC's running AD, DNS, WINs, DHCP, etc, two 2003 exchange
servers (Front End and Back End) a SQL server, a Backup Server, a Application
Mode Terminal Server, and a File and Print Server. Everything is new, 2003,
latest hot fixes, current Antivirus (Symantec Corporate all servers scanned
clean), and clean event logs.

All the servers are the same hardware with the same Intel Pro1000 Nics
plugged into a single 3com gigabit switch. There are no other devices
plugged into this switch.

In my testing I disconnected the uplink port from the server switch and all
other switches calmed down, then I re-uplinked the server switch and powered
off all servers and traffic again basically came to a halt. I powered up the
First DC and it started chatting on every port on every switch about once a
second. I watched the numbers on the packets sent and received and it was
sending a packet about once a second, (and it never stopped) while the
packets received stayed at 14. As I powered up the other servers the network
traffic increased exponentially.

Any further troubleshooting ideas would be appreciated.

Thanks in advance

Sounds like you have a broadcast storm which is normally caused by a faulty
NIC(s) or mis-configured NICs. You need to analyze the traffic immediately
with Ethereal, NetMon, or Sniffer to find out what is really going on.

--
Todd J Heron, MCSE
Windows Server 2003/2000/NT
----------------------------------------------------------------------------
This posting is provided "as is" with no warranties and confers no rights

"Rob Scott" <(E-Mail Removed)> wrote in message
news:EC66C773-BD71-4901-9DE0-(E-Mail Removed)...
> In my testing I disconnected the uplink port from the server switch and
all
> other switches calmed down, then I re-uplinked the server switch and
powered
> off all servers and traffic again basically came to a halt. I powered up
the
> First DC and it started chatting on every port on every switch about once
a
> second. I watched the numbers on the packets sent and received and it was
> sending a packet about once a second, (and it never stopped) while the
> packets received stayed at 14. As I powered up the other servers the
network
> traffic increased exponentially.

You were on the right track here except that you don't want to power up
additional server with the first one still on. Leave the servers running,
you don't have to power them down. Unplug them all,..plug them in and unplug
them one at a time. This should verify which server it is originating from.
It is probably a broadcast strom as Todd suggested.

--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com

Thanks Phil!

--
Todd J Heron, MCSE
Windows Server 2003/2000/NT
----------------------------------------------------------------------------
This posting is provided "as is" with no warranties and confers no rights