Xmail and SMTP Relaying
 

Hi,

I was able to setup xmail on my CentOS box. I have disabled SMTP Relaying but instead I have allowed the following in my smtprelay.tab

"127.0.0.1" "255.255.0.0" --> For webmail access
"192.168.0.0" "255.255.0.0" --> LOCAL LAN Access

This works fine when the users configured with email client is within the LAN area, they can send and receive emails.

However, whenever they are outside the LAN or remotely accessing their emails they can check and receive their emails but they cannot send. The server would reply "550 Relay Denied". Do you have other methods to allow SMTP Relaying without having my mail server Open-relayed?

This is important for roadwarriors who would want to access their emails and use the existing SMTP Server.

What is the difference between POP3 before SMTP and SMTP Auth? Can you please advice?

Thanks and Regards.

Hello,

I do not know xmail, but this behavior is standard in others MTA.
POP before SMTP creates a temporary permission to relay emails from the address used by the user when authenticated via pop-3 (so, you need to check your pop-3 mailbox before send messages).
SMTP auth asks the the user for his password when he tries to send the message from an source address no allowed to relay (different from "192.168.0.0" or "127.0.0.1").
These are the ways to send messages safely when you're outside of your network.
Another option could be create a VPN that puts the roadwarrior "inside" your network (with an allowed address).

Regards,
Tulio Munhoz

Hi Tulio,

Thanks. What approach is the safest? Is it the POP beofre SMTP or the SMTP Auth? What MTA are you using and from your experience which is the best? I have setup Xmail because it is easier to do. But if you can suggest a good MTA which is easier to setup let me know. I want to incorporate SpamAssassin. Is there such a package that includes it?

Thanks.

Hi depam,

Some time ago, some clients could not work perfectly with POP before SMTP (when you did click in "send and receive" instead they authenticate in pop before send the messages, they tied to send the messages first). So since then, I've used SMTP auth and I don't know the POP before SMTP status today.
I've used postfix for years without problems.
I also worked with qmail, but I think that postfix easier to setup and administrate (my personal opinion).
You can easily integrate spamassassin and/or an anti-virus with amavis (http://www.ijs.si/software/amavisd/)

Hi tuliojm,

Thanks a lot for the info. I hope I can try the postfix MTA some other time if time permits. Can you point me to the right resource for starters? Thanks.