UDP nat question

Filipe Abrantes fla at inescporto.pt
Wed Apr 20 18:11:49 CEST 2005


First of all, thanks for replying, it's clear now.

I have one more question related to this:

Imagine a host behind NAT with IP 192.168.22.33 which has an application 
on port 5060 ( a sip client) and opens a connection to a server outside 
the NAT (the sip registrar with IP 130.11.22.33 on port 5060), and 
consider that the NAT box translates the SIP client src_ip to 
129.11.22.33 and src_prt to 5054, for this communication.

The SIP registrar is able to reach the SIP client running on 
192.168.22.33:5060 by using 129.11.22.33:5054, but what about other 
hosts on the Internet? Will they also be able to reach the SIP client 
using the pair 129.11.22.33:5054, or only packets coming from the SIP 
registrar be accepted?

Thanks again

Filipe Abrantes

-- 
Filipe Lameiro Abrantes
INESC Porto
Campus da FEUP
Rua Dr. Roberto Frias, 378
4200-465 Porto
Portugal

Phone: +351 22 209 4266
E-mail: fla at inescporto.pt




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