Date: Mon, 8 Dec 1997 10:37:46 -0700 (MST) From: Charles Mott <cmott@srv.net> To: Valter Mazzaro <teima@kk.etx.ericsson.se> Cc: hackers@FreeBSD.ORG Subject: Re: natd settings problem Message-ID: <Pine.BSF.3.96.971208101859.22059B-100000@darkstar.home> In-Reply-To: <199712081643.RAA05250@kk660.kk.etx.ericsson.se>
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On Mon, 8 Dec 1997, Valter Mazzaro wrote: > My purpose is to run a video conference application (vic) between HOST1/2 and > ISP. > In AS a natd daemon is running. The problem is that, with the present settings, > I've succeeded in running vic just between ISP and ONE host AT THE TIME!! [snip] > permanent_link udp 192.168.104.10:4444 193.10.15.157:0 4444 > permanent_link udp 192.168.104.10:4445 193.10.15.157:0 4445 > > Vic uses 4444 and 4445 as known ports to establish the connession and to > exchange data. With this conf file I don't have any problem in let HOST1 > and ISP interact. > > If I try to connect also HOST2, adding in the natd.conf: > > permanent_link udp 192.168.104.11:4444 193.10.15.157:0 4444 > permanent_link udp 192.168.104.11:4445 193.10.15.157:0 4445 The problem is that you cannot simultaneously redirect a single port on the aliasing host to two distinct machines (192.168.104.10 and .11). Now, if you had two registered addresses for your natd box (perhaps 193.10.15.155 and .156), it would be possible to do something like redirect_port 192.168.104.10:4444 193.10.15.155:4444 193.10.15.157:0 redirect_port 192.168.104.10:4445 193.10.15.155:4445 193.10.15.157:0 redirect_port 192.168.104.11:4444 193.10.15.156:4444 193.10.15.157:0 redirect_port 192.168.104.11:4445 193.10.15.156:4445 193.10.15.157:0 I don't know that you can get two registered IP addresses, so this probably isn't too useful to you. The problem is that when you redirect the same address/port combination to more than one machine, only the last machine you designated gets the traffic. It might be possible to add a internal broadcast function to natd so that video conferencing would work. I seem to remember there is broadcast support in the UDP protocol, so may be the packet aliasing engine used by natd could take this into account. Charles Mott
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