FW: Dell Poweredge 1950 - network connectivity issues

[Brian Lynn]

In case no one has found an answer to this, yet, I've found a couple of
interesting things:

-          when there is trouble with the networking, ping reports latencies
in the 40-50 ms range from a locally connected computer.  When the
networking is fine, ping latencies are << 1 ms.

-          it seems that poking about with the system (e.g. using the
console keyboard to cancel the screen saver) can sometimes unstick the hung
network connections.

-          often after a putty ssh connection has been idle for some
minutes, the next keystroke will be processed correctly and echoed back, but
subsequent ones will hang, at least for a time.  (Sometimes only a few
seconds, sometimes several minutes).  A packet sniffer shows TCP packets
with out-of-order indicators, duplicate acks, and retransmissions.

-          even when putty is hung, ping still works, so the problem may be
in the tcp layer

-          if enough connections get hung, it seems that rebooting the box
is the only quick solution to re-establishing connectivity.

 

I don't think DHCP is the issue, as this box has a static IP and my DHCP
range is higher, so I don't think that there's a conflict.

 

All in all, it looks like a possible device driver issue.  However, this is
a brand new box, and the drivers on Dell's support site appear to be the
same as I have installed.

 

One point is that I only have 1 of the two Ethernet connections active in
the dual Gigabit Ethernet adaptor, though I don't see that this should be a
problem

 

- Brian

 

 

<<Fwd of previous message>>

 

Red -

 

I'm following up on your message about network connectivity issue on a
PowerEdge 1950.  I am having identical problems with a similar configuration
(slight hardware differences), except I'm running RHEL4.  Did you ever get a
solution to your problem?

 

-          Brian

 

See your original message attached below.

====================================

Hello I am running the following set up:
 
A dell poweredge 1950: running Ubuntu Dapper Drake 6.06.1 LTS with lvm and
raid
 
 
   - 1x Dual Core 64-bit Intel(r) Xeon(r) 5050, 2x2MB Cache, 3.00GHz, 667MHz
   FSB
   - 2GB 533MHz (4x512MB), Single Ranked DIMMs
   - 2x 146GB,SAS, 3.5-inch, 10K RPM Hard Drive
   - Integrated SAS/SATA RAID 1, PERC 5/i
   - Redundant Power Supply with Y-Cord
 
 
Everything is fine on my server except for that fact that everytime I try to
connect the connection times out at first. It can take as much as 1 minute
for the connection to work.
 
Then after a while my putty sessions, ssh session, apache sessions time out.
 
I've used tcpdump to look for network card errors and there seems to be
none. I've look through the logs no refused connections for apache.
 
I have the Broadcom NetExtreme Dual Gigabyte Ethernet and I'm starting to
think maybe there is some weird problem with the bnx2 driver in the kernel
I'm running.
 
Linux cando 2.6.15-26-amd64-generic #1 SMP PREEMPT Thu Aug 3 02:52:35 UTC
2006 x86_64 GNU/Linux
 
Another possibility I thought of is that some kind of power managment or
wake on Lan function is causing problems.
 
However I booted up with ACPI=off so I thought that would disable power
managment.
 
Where do I begin with this , it seems to be quite elusive and I can't get a
straight answer anywhere.
 
My ip is static but I know it's on a DHCP network so I was also wondering if
I'm having DHCP conflicts. I have to check with the network admin tomorrow
about that.
 
 
Summary:
First connect = wait 20s-1min with timeouts
 
SSH, Apache, Putty session reset or timeout, then 20s-1min later all seems
fine.
 
The interval is about every 10-30minutes.
Static IP behind nat 10.0.0.0 network
 
Thanks in Advance for your help. Any clue would help.
If I can't figure this out soon my impulse is to replace the Broadcom Dual
Ethernet with an Intel Pro Dual or single Gigabyte Ethernet card.
I'd really like to avoid this if possible so see if you can give me a lead.
 
Thanks,
 
Red

 

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