Connection log entries - random port number recorded

Started by mike galmost 22 years ago3 messagesgeneral
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#1mike g
mike@thegodshalls.com

Hello,

I have postgres set to log all connections. I run it on port 5432. I
have noticed in the postgres logs that the port being used to connect to
the database is logged but never equal to 5432. The ip address recorded
is correct but the port number recorded is always a different number
each time.

This is 7.4.1-3 on cygwin. Has anyone noticed this on other platforms?

Mike

#2Richard Huxton
dev@archonet.com
In reply to: mike g (#1)
Re: Connection log entries - random port number recorded

mike g wrote:

Hello,

I have postgres set to log all connections. I run it on port 5432. I
have noticed in the postgres logs that the port being used to connect to
the database is logged but never equal to 5432. The ip address recorded
is correct but the port number recorded is always a different number
each time.

This is entirely normal. The database listens on port 5432, but the
client will connect *from* a randomly chosen port (it's not actually
random, but it is meaningless).

You can't have two connections with the same endpoints, i.e. if you open
up one connection and it goes:
client:12345 => server:5432
then the next outbound connection will have to use a different port e.g.
client:12346 => server:5432

On linux you can use "lsof -i" to see all current connections, I used to
use something similar on Windows, but can't remember what it was.

HTH
--
Richard Huxton
Archonet Ltd

#3Matt Van Mater
nutter_@hotmail.com
In reply to: Richard Huxton (#2)
Re: Connection log entries - random port number recorded

On linux you can use "lsof -i" to see all current connections, I used to
use something similar on >>Windows, but can't remember what it was.

The tool you're looking for is called fport, and is distributed for free by
Foundstone. It lists which program is using each open port. Alternatively
you can just use netstat -an to just see which ports are actively
communicating or listening, but it won't show you which program is using
that port.

Matt

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