Fedora core 1 sendmail problems

[Alexander Dalloz]

Am Mi, den 31.03.2004 schrieb Homer Sapions um 04:38:

> 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.

Ok, let me say that what I had in mind before, but as you said in your
initial posting - the same configuration did run before with RH 7.3 as
the Linux system - I did not pointed to that possibility: your ISP may
filter outbound (coming from your side) connection on port 25. This is
meanwhile done by many provider for dialup connections to pretect agains
misconfigured email servers acting as open relays. You might ask your
ISP whether he begun to filter on port 25.

If I did understand your description above right, then connects from at
work through port 80 to the Sendmail on your Fedora is running fine.
That would clearly tell me that your ISP is blocking specific traffic.

The only thing which still confuses me is the fact, that when I tried to
connected your Fedora Sendmail host behind the router on port 25 you had
seen this traffic using tcpdump, but as you said you did not see this
incoming traffic in the sendmail /var/log/maillog. And I did not get any
response back. Just a hanging connection waiting for timeout.

Homer, it might be a help for you, if you contact me again by private
mail and we agree a date when you connect your Fedora host direct to the
net, without any router in front. This way we could be sure whether the
ISP does filtering or whether the problem is within your private net and
configuration. Just let me know if you would like to test this way.

Alexander


-- 
Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13
Fedora GNU/Linux Core 1 (Yarrow) on Athlon CPU kernel 2.4.22-1.2174.nptl
Sirendipity 05:06:18 up 11 days, 12:48, load average: 0.32, 0.25, 0.16 
                   [ Γνωθι σ'αυτον - gnothi seauton ]
             my life is a planetarium - and you are the stars
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