The following bug has been logged online:
Bug reference: 1191
Logged by: John D. Hendrickson
Email address: johndhendrickson22124@yahoo.com
PostgreSQL version: 7.4
Operating system: Debian testing
Description: odd usage of port 512 on localhost
Details:
Hi,
Since I've installed postgres on debian-testing I'm getting firewall logs
of:
RELATED PACKET:
SRC=localhost DST=localhost PROTO=ICMP CODE=3,3
PROTO=UDP SPT=1030 DPT=512
My logs show it happens every time postgres postmaster sends mail.
Any clue as to why Postgres would want rexecd on localhost? After all, the
inetd author said NOT to allow anything localhost in hosts.allow since
applications can too easily be insecure that way on many OSes.
Postgres doesn't say anything about using remote execution on the localhost
in the documentation. Is this "feature" in the source code somewhere?
As we see, this is a "RELATED" packet which tries to get through. However,
3,3 (I hope) implies that inetd does block access. NOTE! Just the packet
alone is enough to put a hole in most running statefull firewalls.