Thanks a lot! Regards
César ----- Original Message ----- From: "Rich Adamson" <[EMAIL PROTECTED]> To: "Asterisk Users Mailing List - Non-Commercial Discussion" <asterisk-users@lists.digium.com> Sent: Monday, January 31, 2005 9:18 AM Subject: Re: [Asterisk-Users] SIP x NAT > > I have a question for you: > > > > - "SIP doesn't work behind NAT very well" > > > > Do you agree with this sentence? > > Depends. Asterisk behind a nat box tends to be an implementation > problem limited by the knowledge of the person doing the implementation > and somewhat by the functionality implemented within the nat box. > > Sip phones behind a nat box (with asterisk on a registered IP address) > tends to be rather easy, and how well it works depends a lot on how > well the sip phone vendor implemented nat support. > > Both asterisk and sip phones behind different nat boxes tends to be > the most difficult to implement and requires the greatest amount of > knowledge/experience to implement. Again, depends a lot on the > functionality provided in the nat boxes. > > The issue with sip is that session startup and control occurs across > udp port 5060, and the two endpoints (* and phone) negotiate another > set of udp ports for the rtp (voice) session. The choice of which rtp > ports to use was left up to each sip phone vendor, so the udp port > number in use could be anything from about 8000 (xlite) to something > greater then 32,000. > > Some firewall/nat boxes will actually watch the sip rtp negotiation > process by inspecting the contents of the sip packets, and open up the > wanted ports. However, most cheap nat boxes don't do that, and leave > it up to you to statically define/map the ports required. > > > _______________________________________________ > Asterisk-Users mailing list > Asterisk-Users@lists.digium.com > http://lists.digium.com/mailman/listinfo/asterisk-users > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users > _______________________________________________ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users