[vlc-devel] Rép . : Re: commit: Qt4: fix default port numbers in streaming wizard ( Rémi Denis -Courmont )

Marian Ďurkovič md at bts.sk
Thu Nov 26 19:50:33 CET 2009

On Thu, 26 Nov 2009 19:11:18 +0200, Rémi Denis-Courmont wrote
> Le jeudi 26 novembre 2009 18:43:55 Philippe Coent a écrit :
> > but 5004 is conforming to iana no ?
> Yes. 5004 is the RTP port allocated for RTP/AVP over UDP, TCP and DCCP.

Let's quote from the RFC:

   As specified in the RTP protocol definition, RTP data SHOULD be
   carried on an even UDP port number and the corresponding RTCP packets
   SHOULD be carried on the next higher (odd) port number.

   Applications operating under this profile MAY use any such UDP port
   pair.  For example, the port pair MAY be allocated randomly by a
   session management program.  A single fixed port number pair cannot
   be required because multiple applications using this profile are
   likely to run on the same host, and there are some operating systems
   that do not allow multiple processes to use the same UDP port with
   different multicast addresses.

   However, port numbers 5004 and 5005 have been registered for use with
   this profile for those applications that *choose* to use them as the
   default pair.

Thus, default port is application matter. It's nothing like port 80 for HTTP.
VLC is using 1234 for many years and everyone knows that. Such use is
perfectly valid and multiple firewalled networks are configured to handle
it correctly. Those who can't configure their firewall should learn.

> The native RTP receiver already defaults to 5004 in VLC 1.0.

... and that was effectively overriden in the GUI back to 1234 for obvious reasons.

> The Qt4 interface allows changing the port number on the receive path.

Yes, why would we do things easier for the users, when they could be more complex...

> Contrary to 1234,
>  - 5004 is the standard port number,

It's not

>  - 5004 is not commonly used for something else, raw TS over UDP,

That's more a disadvantage. Requires two ports to be opened on the firewall.
And BTW, autoselecting between TS over raw UDP and TS over RTP/UDP is trivial,
older VLC versions were doing it fine. 

>  - 5004 is not allocated to something else.

Which RFC registers 1234 as the standard port for something else?

Bottom line: this discussion evidently doesn't make sense anymore. You already
commited yet another change to the bugfix branch which widened the interop issue
with installed setups even further... 


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