On Sun, 15 Sep 2002 21:58:20 -0600 (MDT), Brook Milligan
<brook@biology.nmsu.edu> wrote:

> One of my NetBSD machines has recently moved to a new network which is
> behind a firewall.  It now has no publicly accessible DNS entry.
> Although all outgoing network services (e.g., telnet, ftp, ping,
> traceroute, http, ssh) work fine, mail delivery no longer does.

Do you mean outbound mail, or inbound?  

Outbound you need permission on the firewall.  If you can "telnet
mail.netbsd.org 25" (or pick your host) then you should be able to send
mail.  Hosts are not supposed to refuse mail for DNS reasons.  If you
cannot, perhaps you could use the internal mail hub as a relay.  

Inbound, yes, you need a domain on the real internet.  

HTH.

--jkl

> I presume that this is because hosts at the receiving end of an smtp
> connection do a DNS lookup and then refuse the connection when they
> cannot find an entry for my machine.  I presume also that the correct
> solution is to obtain a public DNS entry for my machine.