[FFmpeg-devel] [PATCH] Send NAT punching packets when starting to read an RTP/UDP stream

Luca Abeni lucabe72
Thu Feb 11 10:29:29 CET 2010

Hi Martin,

Martin Storsj? wrote:
>> The packets pass through the NAT, and arrive to S from a different 
>> source IP (the NAT public IP) and a different source port (the port on 
>> which the NAT machine remaps the "private" source port used by C).
> If the NAT changes the port numbers, this probably doesn't work. Usually, 
> they don't change the port numbers, though. The "source port, destination 
> port, destination ip" tuple is often enough to keep track of connections, 
> mapping them uniquely to the private IP of C.

But if you have two NATed clients sending packets from the same source
port, won't the source port of at least one of the two be changed?
Consider two ffmpeg clients in the local network, which want to
receive the same stream...
I've seen a good number of NATs remapping the port numbers in this


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