According to this link, https://www.novell.com/support/kb/doc.php?id=7007649 the rp_filter for an interface is based on:

The max value from conf/{all,interface}/rp_filter is used when doing source validation on the {interface}

It also says

When development fixed this deficiency and released that fix in SLES 11 SP1, and SLES 10 SP4 the kernel began validating all incoming packets based on the setting.

Here is what I'm running with.

uname -r:
2.6.16.60-0.85.1-smp

cat /etc/SuSE-release:
SUSE Linux Enterprise Server 10 (x86_64)
VERSION = 10
PATCHLEVEL = 4

and I looked at the kernel source (/usr/src/linux-2.6.16.60-0.85.1/) and the fix wasn't in there. I looked at a SLES 11 SP 1 machine and it did have the fix.

When was this fix backported to SLES 10 SP4? Was it in a later kernel version? I was looking at the list of kernel versions here: http://wiki.novell.com/index.php/Kernel_versions

Is there a way I can get the source for the different kernel versions to look at them and see if the change is in there?

Let me know if there is any other information you need from me! It is very important that I figure out when this change was made.