Fedora core 1 sendmail problems

Wed Mar 31 01:21:47 UTC 2004

Moderately off topic, but I came across a really good sendmail auth article
today, that I bet a few people might find handy.

http://www.joreybump.com/code/howto/smtpauth.html

easy to follow, tho the SSL part may be omitted for those that choose.  

jonathan

-----Original Message-----
From: fedora-list-bounces at redhat.com [mailto:fedora-list-bounces at redhat.com]
On Behalf Of Robert Boucneau
Sent: Tuesday, March 30, 2004 6:49 PM
To: For users of Fedora Core releases
Subject: RE: Fedora core 1 sendmail problems

Hi Homer,

I'm jumping in late here, but I have read all the preceding messages...it
looks to me as though Alexander, et. al. have all the sendmail issues
covered.  If sendmail works inside and you have your gateway properly
configured (which it appears you think you do) then this should not be a
sendmail issue.

To completely rule out sendmail, I'd suggest setting up a telent server to
listen on port 25 (after turning off sendmail) and seeing if you can log in
for the outside.  If you *can* it's sendmail's configuration.  If not, it's
either your OS *or* your network.  (Personally, I'd skip this step and go
right to the networking suggestions below...but this is a valid first
step...)

Put another machine on your email server's IP address and try to connect to
it.  That will either show the problem to be internal or external to your
machine. (I'm guessing external.)

If it's internal to your machine (i.e. you can log onto a different
machine's port 25 from the outside if it is on your server's IP address),
you can troubleshoot the networking components of your system (the Netfilter
(iptables) guys have some pretty clean ways to watch packets transit your
system, if you want to troubleshoot) or reinstall the OS (I'd scrub and
install, myself, but that's just an opinion.)

If it is external to your machine (my guess), then it is either your
firewall/router,  your cable-modem, or the ISP's router.  I'd guess it's
your firewall/router or your cable modem (the cable modem is actually a sort
of router, not a modem, and it has Network Address Translation, too. so it
could be dropping reply packets silently...)

To test this, I'd put a machine on the "outside" of your Linksys
router/firewall and see if it can connect (i.e. eliminate the cable modem)
or I'd remove the firewall/router and see if things work with just the
cable-modem.

My guess is that in one of those configurations you'll be able to connect
from the outside. Whichever device is not connected is the culprit.  I'd
guess it is the cable modem and you'll have to reconfigure NAT on it...

I hope this helps.

All the best,

Bob

-----Original Message-----
From: fedora-list-bounces at redhat.com
[mailto:fedora-list-bounces at redhat.com]On Behalf Of Homer Sapions
Sent: Tuesday, March 30, 2004 10:36 AM
To: fedora-list at redhat.com
Subject: Re: Fedora core 1 sendmail problems

Current status - still not working. I did not manage to work on it much last
night but I intend to try again tonight. Fortunately this is a personal
web/mail server so inbound mail is for myself and a few other family members
only.

Port 25 is not being blocked at the ISP or at the linksys. I can send mail
out with no problems, but can not receive mail. Traffc _is_ definitely
getting to the server on port 25. When I turn on tcpdump or ethereal
watching port 25 I see inbound connections, and I see my server attempting
to respond. Alexander Dalloz spent a lot of time attempting to help me debug
this, doing as I had done previously from another ISP, telnetting to my
server on port 25. He did not get an immediate disconnect, but it took a
number of seconds. During this time, I could see via tcpdump him connecting
to me, and my server attempting to respond, but he never got the ACK back
from my server.

iptables is not running on the server, and sendmail is not behind
tcp-wrappers. I am not aware of any routing problems, because outbound mail
works fine, and all of my web pages are working fine, including
Squirrelmail, CGI scripts etc. I have nothing in /etc/hosts.allow or
/etc/hosts.deny, and I modified my sendmail.mc to comment out the DaemonPort
options listing only the loopback IP address, then built a new sendmail.cf
with make -C /etc/mail, and restarted the sendmail daemons.

Last night I uninstalled iptables and tcp-wrappers to be totally sure there
is no correlation, but did not get as far as rebooting and testing some
more. I had other problems with my cable modem connection and loss of all
internet access for a while. I will try rebooting and testing further as
soon as I get home tonight. I will take a look at your how-to doc also and
see if I can pick up any possible problems from that.

>From: "Rodolfo J. Paiz" <rpaiz at simpaticus.com>
>Reply-To: For users of Fedora Core releases <fedora-list at redhat.com>
>To: For users of Fedora Core releases <fedora-list at redhat.com>
>Subject: Re: Fedora core 1 sendmail problems
>Date: Tue, 30 Mar 2004 08:58:46 -0600
>
>At 13:26 3/29/2004, you wrote:
>>I'm running a server - not a client. On the server I need to be able to
>>both send and receive mail using SMTP on port 25 to/from other servers.
>>I'm not catering for POP mail on port 110.
>
>Homer,
>
>I've lost track of what's going on here. What is your current status and
>problem? Are you sure it's not a network issue (firewall, router, ISP
>blocking the port, etc.)? Try also taking a look at the "Sendmail SMTP AUTH
>HOWTO" on my website [1]. While the concept is not exactly what you want,
>the steps shown for enabling receive from the network should work for you.
>
>[1] http://www.simpaticus.com/linux
>
>Only note that the sendmail.mc included there shows this line:
>    * define(`confAUTH_OPTIONS', `A')dnl
>In reality, the Fedora installation of Sendmail has `A p' instead. Remember
>to remove the "p" or else it won't work; this is an error which I have
>regrettably not fixed yet in the document.
>
>Cheers,
>
>
>--
>Rodolfo J. Paiz
>rpaiz at simpaticus.com
>http://www.simpaticus.com
>
>
>--
>fedora-list mailing list
>fedora-list at redhat.com
>To unsubscribe: http://www.redhat.com/mailman/listinfo/fedora-list

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