Why does sendmail think its host is named `localhost' is it named?

[Harry Putnam]

Kevin Darcy <kcd at daimlerchrysler.com> writes:

> I'm not so sure this is even DNS-related. How is your sendmail.cf 
> configured for name-resolution, e.g. does it look at the hosts file, 
> and, if so, what does the "localhost" entry there look like? Is there 
> are any explicit reference to localhost in sendmail.cf?

(/etc/hosts appears at the end)

Thanks for the response... I've been pondering on this a while.  Where
would such a thing be set in sendmail? There is no reference to
localhost in /etc/mail/sendmail.mc, the configuration file, however to
answer your question, yes there is in /etc/mail/sendmail.cf.
But I built the sendmail.cf from my own sendmail.mc.  Where else would
something like that occur?

A brief look with line references would be:
  grep -n -2 localhost /etc/mail/sendmail.cf

63-# default LDAP map specification
64-# need to set this now before any LDAP maps are defined
65:#O LDAPDefaultSpec=-h localhost
66-
67-##################
--
73-#D{sendmailMTACluster}$m
74-
75:Cwlocalhost
76-# file containing names of hosts for which we receive email
77-Fw/etc/mail/local-host-names
--
663-
664-# handle special cases for local names
665:R$* < @ localhost > $*		$: $1 < @ $j . > $2		no domain at all
666:R$* < @ localhost . $m > $*	$: $1 < @ $j . > $2		local domain
667:R$* < @ localhost . UUCP > $*	$: $1 < @ $j . > $2		.UUCP domain
668-
669-# check for IPv4/IPv6 domain literal
--
1031-R$* u $* $| <@> < $* >	$: <?> < $3 >
1032-R$* $| $*		$: $2
1033:# handle case of @localhost on address
1034:R<@> < $* @ localhost >	$: < ? $&{client_name} > < $1 @ localhost >
1035-R<@> < $* @ [127.0.0.1] >
1036-			$: < ? $&{client_name} > < $1 @ [127.0.0.1] >
1037:R<@> < $* @ localhost.$m >
1038:			$: < ? $&{client_name} > < $1 @ localhost.$m >
1039:R<@> < $* @ localhost.UUCP >
1040:			$: < ? $&{client_name} > < $1 @ localhost.UUCP >
1041:R<@> $*			$: $1			no localhost as domain
1042-R<? $=w> $*		$: $2			local client: ok
1043-R<? $+> <$+>		$#error $@ 5.5.4 $: "553 Real domain name required for sender address"

==============

cat /etc/hosts (parred down):


127.0.0.1	localhost       reader
## ============================
192.168.0.4     reader.local.net0      reader     # gentoo
#===========================================================
192.168.0.3     mob2.local.net0   mob2  # winxp (home)
[...]