topic Re: The strangest network problem. in Operating System - Linux

The strangest network problem.

wobbe — Mon, 17 Aug 2009 21:20:59 GMT

I just installed RHEL 5.3 on a HP Proliant DL380G5. And now I loose about 95% of all pings to that server. Pinging an other workstation or server from this machine works just fine, no packets lost. There's nothing wrong with the server hardware, before I installed RHEL 5.3 it was running Cent O.S. 5.1 without any problems. (Support issues is forcing me to move to RHEL)
Firewall and selinux has been turned off. I even installed the same software, using kickstart, to a vmware server, and that's working just fine. I also installed the latest support pack 8.25 but that didn't help. Before I installed RHEL I upgraded the firmware using the hp firmware maintenance cdrom (8.50 i think)Normally I would think there's something wrong with the network settings hd / fd mismatch, but i use gigabit (copper) and that only works on fd besides i connect to the same switches and experience the problem one way on both nic's
It’s all very weird to me, hope someone can help.

Re: The strangest network problem.

Ivan Ferreira — Tue, 18 Aug 2009 00:32:30 GMT

I would test and verify:

- Using a laptop with a direct cable, the ping command
- Using tcpdump, if the icmp packets are not reaching the server or are not leaving the server
- The error and collisions counters in the ouput of ifconfig and netstat
- That there is no IP address conflict (just in case)
- That everything is correct in the arp table

Re: The strangest network problem.

wobbe — Tue, 18 Aug 2009 05:10:20 GMT

fixed.
Ended up giving new mac addresses to ifcfg-eth0 and ifcfg-eth1 and configuring bonding.
There is something stange going on with linux and 2 nics but unfortunatly I don't have the time to investigate further. I've installed windows on many exactly the same servers on the same network and have never run into these kind of problems.

Re: The strangest network problem.

wobbe — Wed, 19 Aug 2009 08:29:29 GMT

I found the problem and it was with Windowsâ ¦
Well it was the HP network teaming software to be more precise.
I the past this machine had been running windows 2003 and the hard disks with the Windows installation where moved to another server. (Probably due to hardware failure)
But the HP teaming software kept the mac address that was the same as the same as the burned-in mac address. So now there where two the same mac addresses on the network and that not an ideal situation. Within the HP teaming software there is an option that restores the default mac address, I used this to fix the duplicated mac address problem. Now I no longer have to specify a mac address in the ifcfg-eth0 en ifcfg-eth1.