from Neil Parks:
Have just discovered an interesting difference between DOS and Linux in
the way they send email via smtp.
With every DOS and Windoze smtp client I've ever heard of, you have to
specify an smtp host--usually the one provided by your ISP. That's okay
if you always use the same ISP. But if you don't, perhaps because you
have an account on another ISP as a backup in case your main one is down
due to technical difficulties, then it's not so convenient. Chances are
you won't be able to send email unless you change to the backup ISP's smtp
host. Then when you go back to the main ISP you have to remember to
change back.
The only alternative I'm aware of is to find a friendly open relay that
hasn't yet been abused to death by spammers and therefore is (a) still
open and (b) not on the "blackhole list".
Linux, I just learned, makes life much easier. When you send email, you
don't specify an smtp host at all. The smtp client goes out and finds one
that is associated with the recipient's domain. I sent a test msg to
several different addresses using sendmail, and was amazed to see how
quickly and easily it logged onto an appropriate smtp server for each one.
I wonder why Arachne or any other DOS or Win smtp transport client
couldn't do the same.
(end of quote)
Neil, something looks wrong here. Normally email is sent through the ISP one is
connected to. Other SMTP servers, if they are working correctly, bar access
from outsiders. Exception would be free email services that allow SMTP, likely
to be either preceded by POP access or authenticated SMTP. It is the SMTP
server, not the client, that goes out and finds the server associated with the
recipient's domain.
