Mailclients only use external IP

Kevin Darcy kcd at
Tue Oct 29 01:29:41 UTC 2002

Ansgar Brauner wrote:

> Hi guys,
> i've got a problem with my Mail&DNS Configuration.
> There is a small LAN at my home with 4 clients. These clients should
> send mail through a POstfix Mailserver. But on every connect, the
> clients use the external IP the Server (which is also a router) gets
> from my provider. How do i tell the clients to use only the internal IP
> ( The clients get all Information from an dhcp server
> which works fine, i think.
> Some data:
> DNS -> BIND 9.1.0
> MAIL -> Postfix

I'm assuming here that you're also serving DNS to the Internet from that
nameserver, otherwise why would the name of the mailserver resolve to an
external address?

For only 4 clients, I'd probably just hardcode the IP address of the mail
server into the clients' configurations. If you want to do this
"right" however -- e.g. as a learning experience -- look for the phrase
"split DNS" in the archives of this mailing list. With some work, you can
configure your nameserver to give different answers to the same question
from different clients, i.e. the internal clients would resolve the
mailserver name to an internal address, while the external clients would
still resolve it to the external address.

> ps. please excuse my bad english

Seiner Englisch ist mehr besser als meiner Deutsch, nicht war? :-)


P.S. BIND 9.1.0 is quite old and many bugs in it have been fixed in later
releases. You should think about upgrading.

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