Re: [SR-Users] Nathelper module, FLT_NATS, FLT_NATB

I had this thread already starred here in inbox, a wiki page is definitely going to be bookmarked. On Mon, Jun 25, 2012 at 9:44 PM, Daniel-Constantin Mierla <miconda(a)gmail.com > > On 6/25/12 3:34 PM, SamyGo wrote: > > This is a great thread, really full of answers and concepts for me > atleast. > :) > > > looks like we will have a new wiki page with the digested content of this > thread :-) > > Cheers, > Daniel > > > On Mon, Jun 25, 2012 at 5:57 PM, Richard Brady <rnbrady(a)gmail.com> >> Klaus / Daniel >> >> Thanks again for assistance with this. >> >> I've tried the solution based on add_contact_alias() and >> handle_ruri_alias() and it works perfectly. >> >> Richard >> >> On 22 June 2012 13:47, Klaus Darilion <klaus.mailinglists(a)pernau.at> >>> > >> > >> > On 22.06.2012 13:50, Richard Brady wrote: >> >> >> >> Thanks guys, fantastic answers. >> >> >> >> You mention that NAT detection happens before save() and the flag is >> set >> >> by lookup() which makes much more sense. However, if Kamailio is not >> the >> >> registrar, as is the case with my current project, those functions are >> >> not called, so an alternative is needed. There are clearly several >> >> options. >> >> >> >> The solution I have gone for is to replace fix_nated_register() with >> >> fix_nated_contact() so that the REGISTER request is relayed with a >> >> modified Contact header containing the external ip:port of the client. >> > >> > >> > The cleanest solution would be to use add_contact_alias() and >> > handle_ruri_alias(). The do not change the contact but put the public >> > address into a uri parameter. Thus, the URI seen by the client is >> always the >> > one it sends: >> > >> http://www.kamailio.org/docs/modules/3.2.x/modules_k/nathelper.html#id25504… >> > >> > >> >> That is then stored by the registrar (FreeSWITCH in my case) and used >> >> later to originate calls for that user. The FreeSWITCH know to send >> >> those calls to Kamailio through either use of the Path header and >> module >> >> in Kamailio, or through static configuration of fs_path or proxy >> >> parameters in FreeSWITCH. >> > >> > >> > This is fine. >> > >> > >> >> The works for the first INVITE to the registered client behind NAT. But >> >> that client sends back a 200 OK with a Contact header containing its >> >> private IP address, and so fix_nated_contact() needs to be invoked on >> >> that response, and normally it would be due to FLB_NATB being set, but >> >> if Kamailio was not the registrar then that flag is not set. So I need >> >> to detect NAT on the client at the time of receiving the reply, or >> >> alternatively by having the registrar store a cookie and setting it >> >> based on that. >> > >> > >> > You are correct. For in-dialog messages received from SIP clients I >> would >> > always use add_contact_alias() and remove the NAT flags completely. >> > >> >> >> >> I suppose then my next question then is can I call nat_uac_test() on a >> >> UAS? >> > >> > >> > Today, almost any SIP clients are SIP symmetric. This means, that they >> > receive SIP from the some port/connection where they send. Thus, skip >> the >> > NAT tests completely and always use add_contact_alias() for messages >> receive >> > from SIP clients and handle_ruri_alias() for messages sent to SIP >> clients. >> > >> > Depending on if you use Freeswitch also as media relay you can also >> remove >> > the media proxy stuff from the Kamailio config. >> > >> > On important thing is NAT-keep-alive. This is usually done by nathelper >> > module by querying the location table for contact with NAT-flag set. >> Thus, >> > either you do NAT keep-alive by freeswitch (e.g sending OPTIONS >> requests) or >> > do it in your Kamailio proxy (e.g. set the nat_bflag >> > >> http://www.kamailio.org/docs/modules/3.2.x/modules_k/usrloc.html#id2541477 >> > and call save("location","0x02") before relaying REGISTER to freeswitch. >> > Then Kamailio will do NAT-pinging. Note, if you want to keep-alive only >> for >> > successfully registered clients, you man want to call save() in the >> > reply-route of the REGISTER request). >> > >> > regards >> > Klaus >> >> _______________________________________________ >> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list >> sr-users(a)lists.sip-router.org >> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users >> > > > > _______________________________________________ > SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing listsr-users@lists.sip-router.orghttp://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users > > > -- > Daniel-Constantin Mierla - http://www.asipto.comhttp://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda > Kamailio Advanced Training, Seattle, USA, Sep 23-26, 2012 - http://asipto.com/u/katu > Kamailio Practical Workshop, Netherlands, Sep 10-12, 2012 - http://asipto.com/u/kpw > >