[PLUG] nmap and port forwarding questions

[Eric <eric@lucii.org>]

I'm working on a new server behind a firewall that is controlled by a
third party.
The new server is running the latest RedHat (5.4) and iptables is turned
off.

I cannot connect to the postgresql database on port 5432 on the server.
There is port forwarding on the firewall that is supposed to forward to
the database server but no one can connect to it from the outside.

When I scan with nmap from my workstation I get this:  (n1.n2.n3.n4 is
the ip address)

nmap -p 5430-5434 -PN n1.n2.n3.n4

Starting Nmap 4.62 ( http://nmap.org ) at 2009-12-30 08:26 EST
Interesting ports on host-nnnnnn.net (n1.n2.n3.n4):
PORT     STATE    SERVICE
5430/tcp filtered unknown
5431/tcp filtered unknown
5432/tcp filtered postgresql
5433/tcp filtered unknown
5434/tcp filtered unknown

For comparison, this is the same scan but over the port range where ssh
is running (port 13325):

nmap -p 13323-13327 -PN n1.n2.n3.n4

Starting Nmap 4.62 ( http://nmap.org ) at 2009-12-30 08:26 EST
Interesting ports on host-nnnnnn.net (n1.n2.n3.n4):
PORT      STATE    SERVICE
13323/tcp filtered unknown
13324/tcp filtered unknown
13325/tcp open     unknown
13326/tcp filtered unknown
13327/tcp filtered unknown

An internal scan shows the port 5432 as "open".

What does "filtered" mean? 
Shouldn't port 5432 be "open"?


TIA:

Eric

-- 
#  Eric Lucas
#
#                "Oh, I have slipped the surly bond of earth
#                 And danced the skies on laughter-silvered wings...
#                                        -- John Gillespie Magee Jr

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