Local Lookups Fail When the Net is down.

[Martin McCormick]

	We are using BIND 9.7.7 with recursion. Our boarder
router temporarily failed completely isolating our campus from
the rest of the internet.

	During that time, it was impossible to do local lookups.
We were showing 997 out of 1000 recursive clients which is no
surprise but the loss of local resolution effected our telephone
system which is migrating over to VOIP + any other lookups a
client might do that at least in theory should still work
because they are making queries for hosts in our master zones.

	I have been here for a bit over 20 years and we have
lost all connectivity only a very few times, but I had actually
begun to think that newer versions of bind would still provide
local resolution. The systems running the master and slave DNS's
continued to run as they have plenty of resources, but there was
no local resolution.

	Is there anything short of internal and external-facing
DNS's that we can do to be sure that local resolution stays up?

Thank you very much.

Martin McCormick Stillwater, OK 
Systems Engineer
OSU Information Technology Department Telecommunications Services Group