[TriLUG] e-mail configuration question

[Ed Hill]

On Thu, 2002-02-07 at 11:19, gregbrown at mindspring.com wrote:
> All:
> 
> I am attempting to use my Linux lab machine as my primary source for 
> e-mail while at work.  E-mail works great as long as it is sent 
> between users on the same machine (i.e. mail -s "test" username) but 
> when I attempt to e-mail my account from outside of my machine (i.e. 
> sent to username at vtcdev.gc.lucent.com) the mail never arrives.  This 
> happens when I send e-mail from outside of Lucent or from the Lucent 
> network (just from a different machine on the network).


Its good that you checked the firewall.  Next, check that sendmail is
actually listening to all hosts (not just localhost) using:

  netstat -an | grep ^tcp | grep 25

and you should see something like:

  tcp        0      0 127.0.0.1:25     0.0.0.0:*        LISTEN

or 

  tcp        0      0 0.0.0.0:25       0.0.0.0:*        LISTEN

If you see the latter, then sendmail is listening to all hosts.  If you
see the former, then sendmail is listening only to localhost and you
need to go into your sendmail config file (/etc/mail/sendmail.mc) and
change the following:

dnl This changes sendmail to only listen on the loopback device127.0.0.1
dnl and not on any other network devices. Comment this out if you want
dnl to accept email over the network.
dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')

and update.

Note that Red Hat does this as a default to keep sendmail more secure. 
It could be your problem.  But I don't know what distro you're actually
using as you didn't specify...  :-|

Ed


-- 
Edward H. Hill III, PhD
Post-Doctoral Researcher   |  Email:       ed at eh3.com, ehill at mines.edu
Division of ESE            |  URL:         http://www.eh3.com
Colorado School of Mines   |  Phone:       303-273-3483
Golden, CO  80401          |  Fax:         303-273-3311
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