From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason White Subject: Forcing source port with NAT Date: Mon, 23 Jun 2003 14:54:59 -0500 Sender: netfilter-admin@lists.netfilter.org Message-ID: <20030623195459.GA28900@jdwhite.org> Mime-Version: 1.0 Return-path: Content-Disposition: inline Errors-To: netfilter-admin@lists.netfilter.org List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: netfilter@lists.netfilter.org Greetings, I have an application, Zephyr Messaging Service, which uses a client application that sends out UDP packets on port 2104. The Zephyr server will refuse packets from the client if the source address is not 2104. I want to run this application behind a NAT on one given machine. I need a way to ensure that packets from this one machine with a source address of 2104 go through the NAT that they emerge on port 2104 of the external ip address. To diagram a packet: [Intenal machine-10.0.0.2:2104] --> [NAT internal: 10.0.0.1] --> [NAT external: 200.200.200.200: 2104] --> ///internet/// ... Basically, I need to ensure that anything coming in on 200.200.200.200:2104 goes to 10.0.0.2:2104 and anything going out from 10.0.0.2:2104 goes out 200.200.200.200:2104. I know how to map the external to internal, but internal to external isn't immediately obvious Thanks, -Jason -- Jason White (jdwhite@jdwhite.org) http://www.jdwhite.org/~jdwhite Jabber:jdwhite@jabber.org IRC:irc.netbsd.org/{jdwhite,jdw} AIM:jdwhite90125 Yahoo:jdwhite89 ICQ:9295078 MSN:jdwhite89@hotmail.com GPG KeyID: 0x74CF850D/1F57 465A 1357 BA39 2BEF 5629 6E1C 2B20 74CF 850D