[OpenSIPS-Users] [OpenSIPS-Devel] Why the best response is 408 instead of 486 when parallel forking?

Iñaki Baz Castillo ibc at aliax.net
Mon Oct 27 21:38:57 CET 2008

El Lunes, 27 de Octubre de 2008, Dan Pascu escribió:

> So are you saying that we should base the selection logic in the proxy on
> the assumption that devices are well behaved and won't send a 6xx? What
> if a proxy sends a 6xx because a clueless admin wrote a script where he
> used 6xx because he thought they are better? Will you contact all the
> proxies/devices/gateways out there and ask them nicely to fix their
> behavior because your proxy cannot work properly? Don't you see someone's
> ability to cause DOS using this?

Dan, I'm completely anti-6xx responses, in fact you can read this thread from 
me in sip-implementors:

In fact, the only I don't like in my prefer softphone (Twinkle) is the fact 
that it uses 603 to decline a call instead of 480/486.

But note that OpenSers/OpenSIPS/Kamailio already has an option in "tm" module 
to dissable 6XX behaviour (don't break parallel/serial forking):
  disable_6xx_block == 1
(in fact I patched my OpenSer in production with that option 1 minute after it 
was submitted XD).

I just say that being RFC3261 puristic means allowing 6XX painful behaviour. 
And if the proxy administrator wants that behaviour then a 6XX response wins 
over [345]XX.

In conclusion, we have already a way to dissable 6XX "feature" as a "tm" 
option, so we don't need to change it in the official proxy behaviour.


Iñaki Baz Castillo

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