receiving mail

[Sahil Tandon]

On Tue, 13 Jan 2009, Pieter Donche wrote:

> Between host1 (non-freebsd) and host2 (freebsd 7), sending a mail from  
> host1 to host2 (both in domain  .domain.topdom) results in message  
> 'Returned mail: see transcript for details":
>
>    ----- The following addresses had permanent fatal errors -----
> <user at host2.domain.topdom>
>
>    ----- Transcript of session follows -----
> 550 5.1.2 <user at host2.domain.topdom>... Host unknown (Name server:
> mailhost.domain.topdom: host not found)
> -------------

The MX for host2.domain.topdom is mailhost.domain.topdom; the latter is
unreachable by host1, hence the permanent failure.

> mailhost.domain.topdom does not exist in DNS, but host1 can send
> mail to other mailservers all over the world.

The fact that host1 can send mail anywhere else is irrelevant; fix the MX
entry or make mailhost.domain.topdom real/reachable from host1.  Or remove
or adjust the MX entry for host2.domain.topdom so host1 sends mail to
host2.domain.topdom instead of its mailhost.domain.topdom.

-- 
Sahil Tandon <sahil at tandon.net>