How to get mail to local destinations delivered?

[Tim]

John Summerfield:
>> There is nothing special about that, I've done it, Tim's done it. We both 
>> use our own DNS. You don't, and that _might_ be the significant difference.

Chris G:
> Yes, I guess it could be.  Reading the O'Reilly sendmail book it does
> appear to be saying that sendmail uses DNS for *everything*.

I seem to recall that, too, as being one of the reasons I got DNS
working.  The hosts file is really inadequate for a number of things.
My ISP had a crappy DNS server, so I had even more motivation.

> The workaround (well, discovery of what sendmail thinks 'here' is) is
> that mail sent to  <user>@isbd.net from my home system gets delivered
> locally.  Thus if I put:-
> 
>     root:       chris at isbd.net
> 
> at the end of /etc/aliases I get root's mail.  I'd dearly love to know
> *why* sendmail thinks my home system is called isbd.net but I think
> that's lost in the guts of sendmail somewhere.  There is no 'isbd.net'
> anywhere in my system, the only way that sendmail can be obtaining it
> is by removing the 'home' from 'home.isbd.net'.

As I said earlier, it's something like:  Find the local IP address for
the hostname, do a reverse lookup, it gets the hostname & domain name
from that.

If your hosts file had the 127.0.0.1 line with *nothing* other than
localhost.localdomain and localhost in it, then it ought to think that
it's localhost.localdomain.

If it thinks its anything else, you'll probably have to modify some
sendmail parameters to ensure that your local domain name is treated as
local.

> Out of interest a little 'C' test program from the O'Reilly Sendmail
> book which purports to get names in the way that Sendmail does
> produces the following output on my system:-
> 
>     hostname = 'home'
>     canonical = 'home.isbd.net'
>     alias: 'home'


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