Is this the right way to do it ?

[andrzej]

I send mail using sendmail. http://www.linuxnewbie.org/ubb/wink.gif
It's accessible only through interface 'lo'. (Port 25 is firewalled against any connections through 'eth0').

Is it OK ?

The reason for I'm asking is that today, 5s after sending an email I received from the target host, 10 'SYN' packets coming to my port 25.
(My ipchains merrily rejected those packets :P ).

Why should the host I send mail to try to connect ? (AFAIK it's a big ISP's server).

Thanks !
Andrzej

[jemfinch]

Why should the host I send mail to try to connect ?


Because if the mail bounces, the host you sent to needs to send you the bouncing mail.

Jeremy

[posterboy]

Exactly, also most mail programs do not accept your word for who you are, they look you up. When this fails, you get a line in the log that says "may be forged". Some mail programs even insist on having identd or some variant of that running, also. Ray


------------------
ray@raymondjones.net
HTTP://www.raymondjones.net

[andrzej]

So I should learn how to edit sendmail.cf ?
(fortunately mine doesn't allow relaying, it does however allow VRFY). OK, VRFY doesn't bother me.

There are no known exploits on sendmail 8.9.3, I hope ? It should be safe to expose it to the big, evil internet, with default configuration (Mdk 6.1).

Thanks for replying. I now understand it a bit better.

Andrzej

[jemfinch]

Don't learn how to edit sendmail.cf, learn how to install and configure postfix, a much more secure, faster, and easier to configure smtp server.

Jeremy