Wednesday, January 19, 2011

ping6 and slow responses

While trouble shooting an IPv6 issue, I discovered that "ping6 <my_ipv6_host>" was getting very delayed responses.

After running tcpdumps and every other debug method I could think of, I finally determined with the help of a friend, that reverse DNS was not setup for <my_ipv6_host>. After fixing this, the ping6 time was like it should have been.

So, do you have a slow ssh or slow ping6 times?
Check for valid reverse DNS.

Wednesday, January 5, 2011

IPv6 and neighbour soliciting

In dealing with a FireWall Router mf-firewall [1] setup and testing, I ran into an issue where my interfaces on my linux box looked like this:

Bonded Interface -> 2 network real network cards
  creating device bond0:
Vlan2
Vlan3
Vlan4
Vlan5

The vlan interfaces where all based on the bond0 device, so all traffic went into the vlan device, than off course exited the bond0 device.

Doing a tcpdump on vlan5 for a workstation located there, I could not see the neighbour requests. Doing the same dump on bond0 I could see it.
Of course the device on vlan5 was not getting the neighbour solicit command.

Finally after some research I was able to fix this with this command:
" echo 1 > /proc/sys/net/ipv6/conf/all/proxy_ndp "

Hopefully this can save someone else some grief.
Perhaps someone else has a better fix.

[1] http://code.google.com/p/mf-firewall/