There's a local mail gateway for all inbound / outbound mail. Internal
sendmail clients get configured to listen on loopback only and to send
everything to the mail gateway:
define(`SMART_HOST', `mailhost$?m.$m$.')dnl
define(`MAIL_HUB', `mailhost$?m.$m$.')dnl
define(`LOCAL_RELAY', `mailhost$?m.$m$.')dnl
FEATURE(`stickyhost')dnl
FEATURE(always_add_domain)dnl
EXPOSED_USER(`root')dnl
FEATURE(`no_default_msa',`dnl')dnl
FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
MAILER(smtp)dnl
This works whether or not the destination user is known to localhost, and
whether or not the localhost is part of the local authentication domain
(not all machines are ...). FWIW, mailhost is configured to relay all
'trusted' machines on the local LAN.
More Linuxen are showing up with postfix already present; it might be
preferable to "simply" configure postfix to have the same behavior and
avoid the sendmail installation altogether. However, simply setting
/etc/postfix/main.cf relayhost is not the answer (e.g. it doesn't work
...).
Oct 11 08:27:51 shovel postfix/pickup[7075]: 8C06723FF: uid=0 from=<root>
Oct 11 08:27:51 shovel postfix/cleanup[7100]: 8C06723FF:
message-id=<20121011122751.8c0672...@gravel.sandbox.com>
Oct 11 08:27:51 shovel postfix/qmgr[26673]: 8C06723FF:
from=<r...@gravel.sandbox.com>, size=461, nrcpt=1 (queue active)
Oct 11 08:27:51 shovel postfix/local[7102]: 8C06723FF:
to=<hodg...@gravel.sandbox.com>, orig_to=<hodgson>, relay=local,
delay=0.15, delays=0.11/0.01/0/0.03, dsn=5.1.1, status=bounced (unknown
user: "hodgson")
Oct 11 08:27:51 shovel postfix/cleanup[7100]: 9EF9D3B25:
message-id=<20121011122751.9ef9d3...@gravel.sandbox.com>
Oct 11 08:27:51 shovel postfix/bounce[7103]: 8C06723FF: sender
non-delivery notification: 9EF9D3B25
Oct 11 08:27:51 shovel postfix/qmgr[26673]: 9EF9D3B25: from=<>,
size=2338, nrcpt=1 (queue active)
Oct 11 08:27:51 shovel postfix/qmgr[26673]: 8C06723FF: removed
Oct 11 08:27:51 shovel postfix/local[7102]: 9EF9D3B25:
to=<r...@gravel.sandbox.com>, relay=local, delay=0.07,
delays=0.03/0/0/0.04, dsn=2.0.0, status=sent (delivered to mailbox)
Oct 11 08:27:51 shovel postfix/qmgr[26673]: 9EF9D3B25: removed
All machines boot DHCP, DNS has correct / proper MX records for the LAN
interface (e.g. eth0) for each host, and dhclient-script does not record
the eth0 address in /etc/hosts (and I can't imagine why one would want to
introduce a manual 'fix' to this 'feature'.
Any guidance would be appreciated.
TIA.
Oscar.
