port 25 email

[Woodchuck]

On Thu, 27 Sep 2007, x x wrote:

> For the email, I'm just trying to do stuff like dmesg | mail -s "Hey"
> username at domain.dom, or just simple emails to say hi to someone. My ISP
> said something like Thunderbird uses port 25 for inbound/outbound
> traffic, but if I use port 25 through telnet or something it is not
> supported or it is blocked. So what do I do for it, how do I use it?

Some tests...

$ ping someplace.notisp.com

If the ping succeeds,

$ telnet someplace.notisp.com 25

If your connection is being blocked by your ISP, you will see
this:

[djv at pequod djv 0:186]$ telnet someplace.notisp.com 25
Trying 192.74.74.1...
telnet: connect to address 192.74.74.1: No route to host

If the network is not being blocked, you will see something like
this:
	... if the host is not listening on 25:

[djv at pequod djv 0:187]$ telnet rachel.chuck 25
Trying 192.168.1.110...
telnet: connect to address 192.168.1.110: Connection refused
[djv at pequod djv 0:188]$ 

	... if the host is listening on 25:
            ... if the host is running sendmail:

[djv at pequod djv 0:189]$ telnet pequod.chuck 25
Trying ::1...
Connected to pequod.chuck.
Escape character is '^]'.
220 pequod.chuck ESMTP Sendmail 8.14.0/8.14.0; Fri, 28 Sep 2007 06:52:15 -0400 (EDT)
	    ... if the host is running postfix:

[djv at pequod djv 0:190]$ telnet mail.myisp.net 25
Trying 201.11.40.65...
Connected to mail.myisp.net.
Escape character is '^]'.
220 md5.myisp.net ESMTP Postfix

type QUIT to quit connections to sendmail or postfix.

We have not sent any mail yet, just tested connections.

Wait for the commands to finish.  It may be few minutes before
they succeed or fail.

Use your own targets, though.  yahoo.com is usually up and usually
accepts connections to port 25.

I suspect at this point that you need to configure sendmail
to use a "SMART_RELAY" at your ISP, and that you have already 
configured Thunderbird to do this, perhaps long ago.  I suspect this
because a straight installation of OpenBSD leads to this situation,
no mail to remote hosts, even other hosts on the same LAN.

The port 25 is always on the *recipient's* end of the email.

Dave
-- 
                      Dude, Dave's not here!