Re: Curious UDP packets

> Hello.  There are messages like this in shorewall's logs.
> x.x.x.x is my site's IP address, both as the source and the
> destination.  I've been told that they're caused by
> postgresql.  Having these messages filtered out doesn't seem
> to affect postgresql in any way.  Does anyone know why
> postgresql would want to talk to itself in this way?
> I'm using postgresql 7.4.7.  My guess would be that this is
> some sort of a heartbeat.
>
> omega kernel: Shorewall:all2all:REJECT:IN= OUT=lo SRC=x.x.x.x
> DST=x.x.x.x LEN=1016 TOS=0x00 PREC=0x00
> TTL=64 ID=21629 DF PROTO=UDP SPT=32769 DPT=32769 LEN=996

The PostgreSQL stats collector uses UDP over a random loopback port. It
should normally use localhost, though and not a "real" IP.

To see if that's it, turn of the stats collector
(start_stats_collector=off), restart postgresql (restart needed ,not
enough to just HUP) and see if they go away.

Another way might be to see if the pg_stat_activity view is empty
(select * from pg_stat_activity). With the stats collector running it
should never be empty - it should contain at least your own process -
but if the stats packets don't get through that's what would happen.

//Magnus