telnet:25 on the right DNS entry ???

[Arvinn Løkkebakken]

newsgroups <catto at qwestinternet.net> wrote in message
news:822adc$sgt at chronicle.concentric.net...
> example: myemail at usa.net
> I tried randomly until I found that to use telnet on the port 25(smtp) the
> right address is NOT usa.net but it is mail.usa.net instead...
> how should a software understand it????
>
> again: it I do telnet usa.net 25 IT WON'T WORK !!!
> I manually guessed mail.usa.net 25 and it's fine but the PC does now
> guess...
> what C/C++ function returns or redirects to the right DNS entry ???


you can't telnet to a host who doesn't excist.. (maybe usa.net excists.. but
it's not an smtp server) look up mx record for the domain to see what the
mail server is.

dig mx domain.com

Arvinn

Arvinn