Fedora core 1 sendmail problems

[Homer Sapions]

I did some testing in a roundabout fashion, and proved that sendmail is 
configured and working the way it should. Because it is much easier to debug 
a problem like this when you see it yourself, I opened a VPN tunnel to one 
of my servers at work. Our firewall is configured to not allow any outbound 
connections on port 25, because all company mail must be sent via our 
internal mail servers/relays. I shut down my web server locally because I 
know that traffic on port 80 is coming in and out.

I added to my sendmail.mc
DAEMON_OPTIONS(`Port=80,Addr=0.0.0.0, Name=MTA')dnl
ran make -C /etc/mail
then stopped and restarted sendmail. I verified that locally I could connect 
on port 80 and get the usual sendmail connection. I then went to another 
terminal session connected via VPN to  one of my servers at work, connected 
to my own server on port 80 and got what I expected - a sendmail prompt. I 
did the normal trickery of mail from: xxx at yyy.com, rcpt to: homer, data etc.
then disconnected.

I checked my local account, and the message is there as I expected. So the 
problem is obviously not with sendmail, it has to be the linksys, the cable 
modem or the ISP. The linksys config is really easy and almost impossible to 
set up port forwarding incorrectly. I'm not aware of any way to configure 
the cable modem. The only problem I am aware of is that the firmware on my 
linksys is rather old (1.42.3, Jan 28 2002) and the latest firmware doesn't 
want to install on it. This may be a problem. At least now I have a definite 
direction (or 3 directions!) to go in.

Thanks everyone for the help and suggestions, I will let you know the 
solution when I find it.


>From: "Robert Boucneau" <rboucneau at tuckernt.net>
>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 17:49:01 -0700
>
>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

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