Re: [gentoo-user] Help with local mail, please

[Arve Barsnes <arve.barsnes@gmail.com>]

On Tue, 13 Feb 2024 at 16:52, Peter Humphrey <peter@prh.myzen.co.uk> wrote:
> For years, I've been using postfix to accept mail from LAN hosts, and from the
> Internet via my ISP. This has never worked as I want it - it's just so complex
> to set up and understand. Well, it is for a bear of little brain like me.
>
> Can someone tell me how to make postfix accept all mail addressed to any host
> or user on the LAN - and not forward any mail to anywhere at all? It's running
> on a single-homed host on the LAN, and all other hosts are also single homed.
> Any of four hosts can originate mail, and I have fetchmail running on the same
> host to collect POP3 mail from my ISP. Dovecot serves IMAP4 to KMail clients
> on the LAN.
>
> At present, postfix is insisting on forwarding mail addressed to root on a LAN
> machine, but it's supposed to be acting on behalf of that machine. Two other
> hosts' mails never show up anywhere.

I'm not sure I quite understood where you're having problems, but I
have a machine that accepts mail from the LAN through postfix, so I'll
show some of my setup. Replace any <> with your hostnames.

On the LAN machine I don't have postfix, I only send mail directly to
the machine with 'sendmail', but I found that I have in
/etc/mail/mailertable:
192.168. smtp:<mail machine hostname>
<mail machine hostname> esmtp:<mail machine hostname>
And in /etc/mail/local-host-names I have set <mail machine hostname> -
maybe that does something, but I send mail directly with sendmail
either way.

On the postfix machine I have in /etc/postfix/aliases:
root:           arve
This should make all mail to root be delivered to me. It also contains
a bunch of aliases that I'm not sure if is necessary:
arve@<hostname>             arve
arve@<hostname>.lan         arve
arve@<hostname>.localdomain arve
arve@<other machine hostname>.lan              arve

In /etc/postfix/main.cf there is this, and I assume at least some of
this makes this all work:
myhostname = <hostname>.lan
inet_interfaces = $myhostname, localhost
mydestination = $myhostname, localhost.$mydomain, localhost, <hostname>
mynetworks = 192.168.0.0/24, 127.0.0.0/8

Regards,
Arve