[TriLUG] OT: DNS not following routes

[Aaron S. Joyner]

Brian Henning wrote:

> Hi Gang,
>   Is it normal for DNS lookups (which are UDP, right?) to not obey
> routing tables?

DNS packets are just that, packets.  They are sent through the same
mechanisms as most all other packets on the box, they use the same
routing table, etc.  I'm hesitant to say they're precisely the same as
ping for reasons I won't go into (google ping raw socket), but for your
purposes they're the same.

Are you sure the server you're trying to make DNS requests to will
return responses to your source IP?  Most random DNS servers on the
internet don't do recursive queries for just anyone (it adds load, and
tends to make sploits like cache poisoning attacks easier).  Check that
first off.  Then, if it's still busted, explain your network setup more
thoroughly, as that's the next-most-likely culprit.

Aaron S. Joyner