Sendmail, DYNDNS, and relaying questions.
 

Background:
Redhat install, running Sendmail.
My Box is on a dynamic IP from my ISP so I use DYNDNS.com to keep everything inline. I also use their Mailhop Relay and Mailhop Outbound. Currently I can receive e-mail by logging in mail.mybox.net, but have to send mail out through outbound.mailhop.org (or something like that I don't remember the full name) And have to send a login and password, which is also my login and password for my DYNDNS service. Now this setup works fine for my one or two e-mail accounts I have on my server, but a few family members want another e-mail, and I don't want to give them my DYNDNS password. Can I setup Sendmail to accept e-mail from users, then send it on its way through outbound.mailhop.org using my login and password? When I try to do this now I get "Relaying denied" from my server. It has been a while since I configed my Sendmail so I am not sure what I have set up exactly.


Rusty

on edit:
Strangely... if they use Webmail it works fine..... My guess is I need to tell my Sendmail that the new users are ok to send e-mail ????

You're heading in the right direction. If your server accepted emails from any remote users, it would quickly become a SPAM pest. It appears to be correctly configured to reject unauthorised requests to send email from users not in your local network. When they use Webmail, they become local users (the apache(?) server actually sends the message locally) which is why they can then send mail.

I can't help with the specifics with sendmail, but I've gone through this process myself with postfix. Typically you would create a secure connection for smtps (using port 465) with the user logging in using their own password. They can then be trusted by your server to send outbound emails as if they were local users. Your remote users need to reconfigure their email application to uses secure connections and to login in to the sending server before attempting to send mail.

Sorry I can't help more (I hate sendmail), so I think Google is a better friend here than I can be :)

I would get rid of the dyndns forwarding service, and just configure sendmail for pop and smtp, just like a real live mail server. The first rule should be to reject all connections, and underneath that rule, place the exceptions. Rules are read from top down. If an exception is listed after a rejection, the exception is granted.