Hey all, I have been trying to read around this and I must say I'm a little confused as to what exactly the SIP client/server should do when attempting to dial a SIP URI, and exactly what records need to be added to the relevant DNS zones.
>From what I understand, should a SIP client make a VoIP call to a telephone >like number (as +44 181 300 4321, then this would resolve to an domain >something like 1.2.3.4.0.0.3.1.8.1..4.4.e164.arpa, and the lookup will be for >a NAPTR record in the ARPA zone. The client could then could receive some >information which transforms the original lookup into as a SIP URN, such as >sip:[email protected]. A second NAPTR record is then looked up, but at this time it will be in the domain.com zone. This rule must also apply if the initial call from the SIP client was made directly to the same SIP URI - correct? So, if the NAPTR record doesn't exist under the domain.com zone (which do not appear to be utilised that often), Linphone then resorts to using the zone A record. Correct? However, the zone may still have an SRV record which indicates the relevant SIP service the calling SIP client can use. So why can't Linphone simply try to lookup the SRV record before falling back to the A record? So the question still is, is there a way to get Linphone to lookup the zone SRV record? After speaking with our DNS guru, they seem to think the NAPTR records are not in widespread outside of the ARPA zone, and as such will not add these records to our own managed DNS zone. Regards, Chris ------------------------------------------------------------------------------------------------------------- From: Swinney C. Sent: 27 April 2012 00:39 To: '[email protected]' Subject: Getting Linphone to lookup SRV records in a DNS zone as well as a NAPTR record Hi All, We have been trialling several SIP client and whilst LinPhone looks quite good, there seems to be a drawback in its implementation when trying to resolve SIP URI domain names to get the registered SIP service for that domain name. We have only added SRV records to the DNS zone in order to point SIP URI lookups to our SIP service. We have register both UDP and TCP on 5060 to point to the public interface for our SIP entrance gatekeeper. However, when you make a SIP call in LinPhone using a URI (e.g. name@domain), LinPhone first gets the local DNS servers then tries to look up a NAPTR record. When this fails, LinPhone simply appends 5060 to the domain name lookup which resolve to the standard A host record. Of course, the IP address resolved is actually pointing to the wrong server - in fact the web server. Other SIP clients do not seem to have this issue and resolve the correct IP address from the SRV record as expected. Example debug output from LinPhone: --------------------------------------------------------------------- message: eXosip_dnsutils_naptr: DNS server (0): localdnssrv.com message: eXosip_dnsutils_naptr_lookup: About to ask for domain.com NAPTR' message: DNS resolution with domain.com:5060 message: getaddrinfo returned the following addresses: message: x.x.x.x port 5060 --------------------------- (Resolved IP address of web server on A record) message: Message sent: (to dest=x.x.x.x:5060) ------------------------------------------------------------------------------- Is there any way to force LinPhone to lookup the SRV record instead of the NAPTR record, or should we have NAPTR records in our DNS zone as well? We also utilise H.323 and IAX. Cheers, Chris _______________________________________________ Linphone-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/linphone-users
