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Re: [TCLUG:1069] sendmail configuration ?



Kapoor, Nishikant X wrote:
> 
> Hi all
> 
> Here is a question for System Administrators.
> 
> I've my Linux box on the local network (genx) inside the firewall and I've a
> mail server(polaris) sitting outside the firewall. Assuming I have access to
> polaris through the firewall, how do I setup my sendmail on genx so that it
> can use polaris to communicate with the outside world. (I'm trying to use
> elm for email, if that matters).
> 
> I'm running RH4.2, kernel 2.0.30 on a Cyrix-150MHz with 96M RAM and 72M swap.
> And sendmail-8.8.5-4, elm-2.4.25-7.
> 

Disclaimer:  I've only done this kind of thing once.  Any sendmail
experts are more than welcome to jump in here and correct any mistakes!

First of all, make double sure that your firewall is not blocking port
25 (SMTP) or port 110 (POP3). I know you said to assume you have access,
but if these two ports are blocked it just ain't gonna work.

Second, it sounds like you want to both send and receive mail on genx
using elm as the mail client.  The default /etc/sendmail.cf comes close
to what you need, but the following changes are necessary:

On genx, edit the /etc/sendmail.cf as follows: 

(1) Setting up sendmail to know about your local domain:
    Find create the line that starts with DD and add your local domain
name
    i.e. DDnspco.com  

(2) Telling sendmail where to send non-local email:
    Find the line that starts with DS and add the name of your mail
server
    i.e. DSpolaris.nspco.com
    Also make sure that polaris is listed in /etc/hosts.

(3) Edit /etc/sendmail.cw.  Add genex.nspco.com and whatever aliases you
use
    for that box.

(4) kill -SIGHUP the sendmail process to make it re-read the config
files.

Now, assuming your mail server trusts your linux box, you should be able
to send mail anywhere.  

To receive mail, you need to do one of two things: either set up
fetchmail on your box to automatically retrieve mail from your account
on the mail server, or set up the mail server to forward your mail to
your box.  Since I haven't done either of these personally (yet), I must
at this point refer you to a relevant How-To: /usr/doc/Mail-HOWTO.gz. 
You'll also get good advice (better than mine!) on the newsgroup
comp.mail.sendmail.

Hope this helps.  We're all learning at this, and sendmail can be a real
bear.

--
Carl Patten
Systems Administrator
Trimodal Inc.
(finally, a slow day at work!)