On Wednesday, Jan 19, 2005, at 09:50 US/Pacific, L. V. Lammert wrote:
Sendmail usually starts by default. Check your running processes:
bash-2.05a$ ps ax PID TT STAT TIME COMMAND 30553 ?? Is 2:28.19 sendmail: accepting connections (sendmail)
What I did on my home machine was to turn on the services network and sshd in runlevel 1 and then 'init 1'. Despite that, nmap still showed smtp open and I was still able to telnet to the mail server. So I ssh'ed to an outside box, that is, outside of the hotel complex I'm staying at, and redid the nmap:
$ nmap 24.217.196.162
Starting nmap V. 3.00 ( www.insecure.org/nmap/ )
Interesting ports on cc3-24.217.196.162.charter-stl.com (24.217.196.162):
(The 1599 ports scanned but not shown below are in state: filtered)
Port State Service
22/tcp open ssh
80/tcp closed http
Nmap run completed -- 1 IP address (1 host up) scanned in 177 seconds
That looks normal. What I suspect is that the hotel is running a proxy or doing some fancy routing on port 25 (perhaps others) and redirecting outbound connections to their own SMTP server. Here are two telnet sessions which demonstrate what I mean:
From my hotel room. Notice the 220 line which says "vbn.0012209.lodgenet.net" :
$ telnet smtp.charter.net 25
Trying 209.225.8.224...
Connected to mail.charter.net.
Escape character is '^]'.
220 vbn.0012209.lodgenet.net ESMTP Exim 3.34 #1 Wed, 19 Jan 2005 10:29:12 -0800
quit
221 vbn.0012209.lodgenet.net closing connection
Connection closed by foreign host.
From the box outside the hotel complex. Notice the 220 line which says "smtp.charter.net" :
$ telnet smtp.charter.net 25
Trying 209.225.8.224...
Connected to smtp.charter.net.
Escape character is '^]'.
220 charter.net ESMTP
quit
221 charter.net
Connection closed by foreign host.
I wonder how many other ports are like that? A poorly routed/proxied network at a hotel may explain why we cannot connect to our VPN from some locations.
Regards, - Robert http://www.cwelug.org/downloads Help others get OpenSource. Distribute FLOSS for Windows, Linux, *BSD, and MacOS X with BitTorrent
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