> Alexander Dalloz wrote:
>
> >Am Do, den 22.12.2005 schrieb azeem ahmad um 16:23:
> >
> >
> >
> >>i got a question n i studied for it but couldnt get satisfied
> >>the question is
> >>how sendmail server comes to know which domain it belongs to
> >>i mean if there is a server mail.example.com
> >>then how mail comes to know that it belongs to example.com domain
> >>Regards
> >>Azeem
> >>
> >>
> >
> >You have to tell Sendmail which domains have to be treated as local -
> >class {w} - or relay - class {R} - domains in a) local-host-names or b)
> >in relay-domains.
> >
> >Alexander
> >
> >
> >
> >
> That is also what the MX record in a domain's DNS is for.
>
> Justin Willmert
<snip>
Actually sendmail,in the absence of any other attempt to inform it will
try to determine the short host name and domain name for system on which
it is running. [see hostname (1)]. An MX record only identifies the
reference, and host to which mail for a host should be redirected. As
in:
hosta [IN] MX N,MXhost
When mail is directed to hosta (e.g. mailbox1@xxxxxxxxxxxxx) it will get
sent to MXhost (e.g. mailbox1@xxxxxxxxxxxxxx) assuming the preference,
N, is lower than the preferences for any other MX records owned by (for)
hosta. The two domains, do main1 and domain2, may or may not be the
same.
N.B.-- You should be careful about the way you specify host names in DNS
resource records, especially whether they are or are not FQDNs.
The DNS MX resource record does not inform sendmail of the domain name
of the host on which it is running, hosta in the above example. By the
time sendmail gets to looking up MX stuff it will have come up with the
value for the "$w" macro. It has been some time since I looked at
sendmail sources but IIRC the owner of the A record is the way sendmail
would prefer to use in the absence of a more explicit setting of $w.
dlg
