I have a server with 2 nics, one (eth0) as a general address for mail server at mail.mydomain.net, at say 10.0.0.10 One (eth1), at say 10.0.0.12, as the ns1.mydomain.net. When ns1.mydomain.net sends zone transfers to ns2.mydomain.net ( separate machine), it sees them as coming from 10.0.0.10, and rejects them as not being from a known master. They should be seen as coming from 10.0.0.12. Can't see anything in the config files that helps. What to do????