Red Hat Bugzilla – Bug 127548
SNAT rule works only for a short time
Last modified: 2007-11-30 17:07:02 EST
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Description of problem:
I am using LVS-NAT on a RedHat AS3.0 server. The lvs part appears to
be working ok. One of the servers behind the LVS director is a mail
server. Outbound connections originating from the mail server need to
be translated to the virtual ip of the mail server, not the ip of the
redirect server. To accomplish this I installed a SNAT rule on the
director like this:
iptables -v -t nat -I POSTROUTING -s 172.28.1.25 -j SNAT
After a reboot the director works just fine for several hours, but
eventually the real server looses all connectivity to the outside
world. This applies to traffic originating from the server as well as
traffic destined for the server and proccessed by LVS rather then
iptables. I have been unable to find any cause for this problem. The
only thing that brings things back to live is a reboot of the director.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Wait for the director to stop passing traffic from the server.
There is no apparent trigger, it just quits working.
Actual Results: The director no longer passes traffic for the server.
The server looses all connectivity to the outside world.
This is a netfilter kernel problem, not a optables userland problem.
This bug is filed against RHEL 3, which is in maintenance phase.
During the maintenance phase, only security errata and select mission
critical bug fixes will be released for enterprise products. Since
this bug does not meet that criteria, it is now being closed.
For more information of the RHEL errata support policy, please visit:
If you feel this bug is indeed mission critical, please contact your
support representative. You may be asked to provide detailed
information on how this bug is affecting you.