[NTLUG:Discuss] Comcast outbound email server

[Eric Schnoebelen]

". Daniel" writes:
- I run my own personal domain at home.  I connect using Comcast.
- I receive email just fine but if I were to send outbound email
- from my IP address, much of the time it is blocked in some way
- because I am operating from a residential IP address.  So I need
- to send to a server that isn't blocked.
-  
- My solution for now is to configure my client software to send
- to alternative outgoing email servers.  For now, I am using my
- domain registrar's outbound server which requires SMTP AUTH.  I
- can set that up on my clients just fine, but I'm lost in setting
- it up on sendmail.  Sendmail, as I mentioned before, invariably
- results in dizziness and nausea.

	Yes, reading sendmail.cf directly can cause dizzyness
and nausea.. (as someone who's written parts of the
configuration file macros, I can easily, and truthfully say
that!)

	You've got to do four things:

	1)	make sure your sendmail is set up for SASL
		authentication. (This is what sendmail uses
		to do SMTP AUTH.)

	2)	configure sendmail (via sendmail.mc) to SMTP
		AUTH and to relay all outbound mail.

	3)	set up the authentication tables for sendmail.

	4)	test, repeating the above as needed.. :)

	To do the above, do the following:

	1)	sendmail -d0.01 -bv root | grep SASL
		It should return a line with SASLv2 (assuming 8.13.5)
		If not, rebuild sendmail with SASL support.

	2)	Add the following to your sendmail.mc, and
		rebuild the configuration file:

			FEATURE(authinfo)dnl
			FEATURE(stickyhost)dnl
			LOCAL_USER(`root')dnl
			define(`SMART_HOST', `esmtp:mail.isp.net.')dnl
			define(`confAUTH_MECHANISMS', 
					`CRAM-MD5 DIGEST-MD5 ANONYMOUS')dnl

	3)	create the authinof database (usually in
		/etc/mail, but where ever sendmail.cf is stashed.)

		It should look like the following (all on one line):

		AuthInfo:mail.isp.net U:authrid I:authnid
				P:password R:realm M:mechanisms

		realm and mechanisms will have to come from your
		ISP.

		Once you've got the file written, use makemap to
		generate a hashed version of it for use by sendmail.

		(more details can be found in the README file
		delivered in the top level of the sendmail 
		distribution. Look for SMTP AUTH)

	4)	test the new cf file using local and remote address.
		
		sendmail -C <cffile> -bv root
			# should stay local
		sendmail -C <cffile> -bv eric at cirr.com
			# should show relaying through your ISP.


	I hope some of the above proves helpful,
		Eric

--
Eric Schnoebelen		eric at cirr.com		http://www.cirr.com
	Anyone can do any amount of work provided it isn't the work he
	  is supposed to be doing at the moment.  -- Robert Benchley