Finding mail exchangers

[ian]

cheers for the help guys


"Paul Wright" <-$P-W$- at verence.demon.co.uk> wrote in message
news:abqnrn$3c9$1 at verence.demon.co.uk...
> In article <0eSD8.57422$7R.66720 at NewsReader>, ian <iwaters at btclick.com>
wrote:
> >hi ive almost finished my mail server for a
> >programming assignment im doing
> >
> >what i need to do now is write some code
> >to find the mail exchanger for a given domain
> >
> >for example if i send mail to iwaters at btclick.com
> >it gets sent to pop3.btclick.com
>
> No, it gets sent to one of
> btclick.com             MX      10 smtp.btclick.com
> btclick.com             MX      5 mail.btclick.com
>
> (this is the output of "host -t MX btclick.com" on Linux. The "dig"
> command would give something similar).
>
> >how can i get a list of all exchangers for domains?
>
> Do an MX lookup using PyDNS: http://pydns.sourceforge.net/
>
> Note that not all domains will have an MX record, so you'd need to check
> for A records if you don't find a mail exchanger.
>
> The right thing for a client program to do is send the mail on to a
> 'smarthost' which will do the lookups for you and handle queuing and
> retries and suchlike. But I'm assuming that, as your assignment is to
> write a server, this isn't an option for you.
>
> --
> Paul Wright | http://pobox.com/~pw201 |