Ok, this question comes about because I noticed that I manually have
to set $mydomain in Postfix. I'm about to set up Samba, too, and
thinking that I might have to manually set the domain name in that,
too, I thought to investigate this. Surely Postfix should get its
hostname & domainname from the system itself, right?
$ hostname
hex
$ dnsdomainname
stroller.uk.eu.org
$ domainname
(none)
$ domainname -v
getdomainname()=`(none)'
(none)
$
This mention of getdomainname agrees with the comments in Postfix's
main.cf:
# The myhostname parameter specifies the internet hostname of this
# mail system. The default is to use the fully-qualified domain name
# from gethostname(). $myhostname is used as a default value for many
# other configuration parameters.
`man domainname` tells me that `domainname` should in particular "show
or set the system's NIS/YP domain name".
Can anyone explain the significance of this, please?
/etc/conf.d/net.example suggests that "it's rare that you would need
to" set a NIS domainname, "but you can anyway", and the Gentoo Linux
x86 Handbook [1] says "if you don't know what [a NIS domain] is, then
you don't have one".
I guess that a typical desktop system might use ssmtp and not need
either postfix or a NIS domainname, however I'm still confused. I
guess the best question I can ask is why Postfix might choose to use
this apparently-less-common config to set its hostname? I really feel
like I must be missing out. It's not a massive hardship to set
$mydomain manually in Postfix on several boxes, it just seems like I
ideally shouldn't have to. Is there anyone who can help clarify for me?
Many thanks in advance for all suggestions,
Stroller.
[1]
http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?part=1&chap=8#doc_chap2
