Quesiton about exim_mainlog, is this a port number?

[jols]

Hi,

In the following log entry:

2013-02-20 15:17:19 SMTP connection from [1.55.37.113]:21775 (TCP/IP connection count = 7)


... Is ":21775" a port number? In other words, are they able to connect some how to send email on a high number port like this?

As far as we know, we only have port 25 open for SMTP connections, but now I am starting to wonder.

 

[quietFinn]

It's the port number in the sender's end.
The port they are connecting to must be 25 (or 26 if configured so).

 

[jols]

Thanks very much. I've been trying to find an answer to that one for well over a year now. Thanks very much again.