Application DNS Caching

microsoft.public.dotnet.framework

28 Mar 2006 4:55 PM

Michael Bray

Has anyone seen a problem in .NET 1.1 Framework where an application caches
its own DNS entries? (I haven't tested on .NET 2.0.)

I have a client/server remoting application where one central server
connects to many clients in order to push configuration to them. At first,
everything works great. But after a period of time (weeks/months) the
server cannot connect to certain clients.

When I run a network sniff of the connection attempt, I see that it goes to
the wrong IP address! I can ping the target client from a command prompt
just fine. If I restart my server then it works again, and I can see that
the connection attempt goes to the correct IP address.

Even if I add an entry in the hosts file to point to the correct IP
address, it doesn't work - that is, it still tries to connect to the old IP
address. This pretty much proves that there isn't a lookup being
performed.

BTW, I have also tried flushing the DNS cache with 'ipconfig /flushdns' and
confirmed that the entries were cleaned out. In fact, I even configured
the maximum TTL to be 1 second.

-mdb