Re: [SR-Users] How to detect NAT during authenticated registration of clients which adjust the headers

There probably is a better way of doing this, but maybe you can store the fact that the first register came from a natted device in the locations table (or a hash). Or maybe add a parameter when challenging where you state the client is natting? Something like this https://kamailio.org/docs/modules/3.1.x/modules_k/siputils.html#id2769802 Hope that helps David On Fri, 28 Feb 2020 at 12:03, Awal Junanto &lt;a.junanto(a)gmail.com&gt; wrote: > Hi, > > We are building a service where we need to detect NAT when the clients > register to our server. We are struggling in analyzing NAT status of some > clients which modify their IP addresses/ports in the headers according to > the value of "received" parameter sent during "401 Unauthorized" response. > > Here's the flow: > > Client->Server > REGISTER sip:... > Via: SIP/2.0/TLS 192.168.0.1:41157 > ;rport;branch=z9hG4bKPj30093e5d-550d-4d4c-a9a2-22c3bd1cda7e;alias > Contact: <sip:user@192.168.0.1:42251;transport=TLS;ob> > ... > Server->Client > SIP/2.0 401 Unauthorized > Via: SIP/2.0/TLS 192.168.0.1:41157 > ;rport;branch=z9hG4bKPj30093e5d-550d-4d4c-a9a2-22c3bd1cda7e;alias;received=1.2.3.4 > WWW-Authenticate: ... > ... > > Client->Server > REGISTER sip:... > Via: SIP/2.0/TLS 1.2.3.4:6201 > ;rport;branch=z9hG4bKPj30093e5d-550d-4d4c-a9a2-22c3bd1cda7e;alias > Contact: <sip:user@ 1.2.3.4:6201;transport=TLS;ob> > Authorization: ... > ... > > By the time the client is authenticated, there is no way to detect > whether the request was coming from a natted device or not by just > analysing the Via or Contact headers. > > Thanks in advance. > > > _______________________________________________ > Kamailio (SER) - Users Mailing List > sr-users(a)lists.kamailio.org > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users > -- Regards, David Villasmil email: david.villasmil.work(a)gmail.com phone: +34669448337 _______________________________________________ Kamailio (SER) - Users Mailing List sr-users(a)lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users