[OpenAFS] RPC service unavailable, windows client, udebug works

[Christian]

Dear all,

on some of our windows clients (win7 enterprise x64, openafs 1.7.31), we
are seeing issues where if I try to access a volume on a given server,
it gives me "RPC service unavailable". This only happens for one of our
two file and db servers, which are both almost identical (the first one
has in fact been cloned from the second one). Servers run openafs
1.6.9-1~bpo7 from wheezy-backports on debian wheezy. While that is
happening, "fs checkservers" reports that particular server as being
down. udebug <server> 7003 works, though, and I can ping that server or
ssh to it just fine. Should I post trace logs and udebug output for
people to look at, or what is the appropriate way to debug this? Thanks
a lot,

Christian

PS: I should add that this particular client we are looking at right now
is on the same subnet as the servers, but connected via a layer 2 bridge
with openvpn. I cannot recall whether or not I have observed this
behavior on clients hooked up directly.