dovecot rejecting connects

[Bernd Petrovitsch]

Hi all!

On Fri, 2019-12-20 at 17:39 -0700, Roy wrote:
[...]
> I created a new VM with Centos 8 and installed dovecot and postfix.  
> Postfix is working fine but dovecot rejects connections from anything 
> but the local machine.
> 
> Locally
> 
>    Trying 10.10.100.157...
>    Connected to 10.10.100.157.
>    Escape character is '^]'.
>    * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE 
> IDLE STARTTLS AUTH=PLAIN] Dovecot ready.
> 
> Machine on same subnet.  Windows, Linux, etc.  Doesn't seem to matter
> 
>    telnet 10.10.100.157 143
>    Connecting To 10.10.100.157...
>    Could not open connection to the host, on port 143: Connect failed
> 
> I made sure the iptables are empty so it doesn't seem to be a firewall issue

In the host or the VM?
Is teh VM switchted or routed with the LAN interface?

> I put some LOG statements in the iptables and it showed the connect 
> packet arriving and the response packet was ICMP type 3 code 13.

Which make it pretty clear that it has nothing to do with
dovecot as such as that's aresponse from the TCP/IP-stack ...

> Any ideas?

Duckduckgo-ing "icmp 3 13" delivers as the 1st link
http://www.networksorcery.com/enp/protocol/icmp/msg3.htm and
13 seem to indicate "Communication Administratively Prohibited."

Your turn;-)

MfG,
	Bernd
-- 
Bernd Petrovitsch                  Email : bernd at petrovitsch.priv.at
                     LUGA : http://www.luga.at