fc3, sendmail, dovecot: cannot receive from outside

[Alexander Dalloz]

Am Mi, den 09.03.2005 schrieb rado um 11:01:

> Hi Alexander,
> ...sorry if I confused you; let me see if I can clarify.
> 
> rivers-bend.com is my domain w/a public ip of 209.205.179.141
> 
> This box right here is rbmain1 [10.0.0.10] running on fc2 which is fully
> updated. It's running dns, sendmail 8.12.11-4.6, dovecot, and other
> things w/no problems.
> 
> the box w/problems is rbmain2 [10.0.0.12] running on fc3 w/no updating
> yet.
> My intentions are to mirror 10.0.0.10 w/10.0.0.12. After it's all set
> up, I'll probably use rsync or something to sync up the 2 machines and
> if/when 10.0.0.10 ever goes down, just run a script on 10.0.0.12 and it
> will take over.
> 
> Now, while setting 10.0.0.12 up, presently I shut down 10.0.0.10 because
> I don't have scripts in place yet. While 10.0.0.10 is down, dns in
> 10.0.0.12 takes over and works fine. 
> 
> Now the problem: using evolution, I can mail to myself i.e. from:
> rado at rivers-bend.com to:rivers-bend.com and it will pop fine.
> I can send mail out to my hotmail acct: radopowder at hotmail.com, and it
> is received...I reply from hotmail to rado at rivers-bend.com, and it never
> comes. Mind you this is in the fc3 sys, [10.0.0.12].
> ok, let's shut down 10.0.0.12 now.
> 
> bring up 10.0.0.10... that's this box. the email reply that I was trying
> to receive in 10.0.0.12 shows up here in 10.0.0.10. 
> 
> Somehow mail is being stopped from being received on 10.0.0.12.

Ok, now I understand.

> here's a list of my open ports:
> 
> [root at rbmain2 ~]# nmap -sT rbmain2
> 
> Starting nmap 3.70 ( http://www.insecure.org/nmap/ ) at 2005-03-09 08:05
> CST
> Interesting ports on rbmain2.rivers-bend.com (10.0.0.12):
> (The 1654 ports scanned but not shown below are in state: closed)
> PORT    STATE SERVICE
> 22/tcp  open  ssh
> 25/tcp  open  smtp
> 53/tcp  open  domain
> 110/tcp open  pop3
> 111/tcp open  rpcbind
> 113/tcp open  auth
> 
> Nmap run completed -- 1 IP address (1 host up) scanned in 0.283 seconds

Seems to be an nmap run on the host itself. To get really counting
output you should port scan from a different host. Else iptables could
block port 25 though.
 
> Don't forget, Alexander, 10.0.0.12 is only up while I'm working on it.
> when I need to check email like this msg list, I have to shut down
> 10.0.0.12 and bring up this machine, 10.0.0.10. I also monitor my
> hotmail acct. regularly radopowder at hotmail.com which could be used for
> testing communication. That's always up.

> John Rose

I guess your gateway forwarding port 25 to the internal host - 10.0.0.10
or 10.0.0.12 - is not changed when the first one is off and thus the
traffic routed to the false host IP. Else check the maillog as the
traffic _must_ reach the 10.0.0.12 host.

Alexander


-- 
Alexander Dalloz | Enger, Germany | GPG http://pgp.mit.edu 0xB366A773
legal statement: http://www.uni-x.org/legal.html
Fedora Core 2 GNU/Linux on Athlon with kernel 2.6.10-1.770_FC2smp 
Serendipity 17:18:57 up 21:03, 16 users, 0.27, 0.19, 0.11 
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