When I installed my sles 10 servers last summer, I disabled ipv6. I also just checked in yast to make sure it's still showing disabled. But /etc/modprobe.conf has these 2 lines:
alias sit0 ipv6
alias net-pf-10 ipv6

I read on another site that I need to run this in the console, then restart:

echo "alias net-pf-10 off" >> /etc/modprobe.conf
echo "alias ipv6 off" >> /etc/modprobe.conf

Is that right? If I've actually been running v6 this whole time, that might explain some things that are really slow.

By the way, the reason I'm checking on this is that I get error messages from some services that indicate "errors" connecting to ipv6, including backup exec and the firewall.