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Old 03-30-2004, 08:17 PM   #1
Registered: Mar 2004
Location: S.F.,Ca
Distribution: FC4
Posts: 82

Rep: Reputation: 15
Ports listening?

When I open/forward a port and I start the Application, shouldnt I see the port in "listening" stage? I currently have a prog running that utilizes 4661 thru 4672 (emule) but I dont see it when I run netstat.....
Linux boxes access the Net, my Win XP box sits behind it running emule..

target prot opt source destination
DNAT tcp -- tcp dpts:6881:7000 to:
DNAT tcp -- tcp dpts:4661:4672 to:
DNAT udp -- udp dpt:4711 to:
DNAT tcp -- tcp dpts:10240:20480 to:
DNAT udp -- udp dpt:41170 to:

root@server:~# netstat -nluta
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0* LISTEN
udp 65208 0*
Old 03-30-2004, 11:59 PM   #2
Registered: Jun 2003
Location: Australia
Distribution: Gentoo/kernel 2.6.2
Posts: 45

Rep: Reputation: 15
nope... because there is no service running on the server that's listening on that port...

the iptables filtering happens at a very low level... it is monitoring the packet traffic and as soon as it sees headers that contain that port info, it changes it and sends it on its way again...

so netstat wouldn't know anything about it ... there'd never be a port opened on the server for it because there doesn't need to be - it's being redirected to another computer
Old 03-31-2004, 08:40 AM   #3
Registered: Mar 2004
Location: S.F.,Ca
Distribution: FC4
Posts: 82

Original Poster
Rep: Reputation: 15
thanks man


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