Re: [SR-Users] Understanding DNS resolution done by Kamailio

Hello Daniel, Sorry, but I’m not sure to understand. Use the resolver included in Kamailio would be better in that case because the negative reply coming from outside resolver would be recorded for a timeperiod? In this timeperiod, no other DNS requests for the same type and the same host would be generated to the outside resolver? I’m right? In parallel, you can confirm that the SRV requests cannot be avoided? Regards, Igor. De : Daniel-Constantin Mierla [mailto:miconda@gmail.com] Envoyé : lundi 4 août 2014 16:18 À : Igor Potjevlesch; 'Kamailio (SER) - Users Mailing List' Objet : Re: [SR-Users] Understanding DNS resolution done by Kamailio Hello, On 04/08/14 14:20, Igor Potjevlesch wrote: Hello Daniel, Thank you. If I use the resolver included in Kamailio and if the response from the resolver is negative, is there a new DNS request sent for outgoing uri resolution? it should not be any other dns request -- it will fail sending. Cheers, Daniel If not, that would mitigate the volume of DNS requests sent. Regards, Igor. De : sr-users-bounces(a)lists.sip-router.org <mailto:sr-users-bounces@lists.sip-router.org> [mailto:sr-users-bounces@lists.sip-router.org] De la part de Daniel-Constantin Mierla Envoyé : vendredi 1 août 2014 08:46 À : Kamailio (SER) - Users Mailing List Objet : Re: [SR-Users] Understanding DNS resolution done by Kamailio Hello, I don't think there is a way to disable dns for outgoing uri resolving, if you want disabling all dns. The dns timeout is can be configured at the operating system level. To avoid the sip worker blocking, you can try: a) look at $nh(d) and if it is not an IP, then you can use async_route() (async_task_route() would be better, but now only in devel) or mqueue+rtimer to pass the relaying of the request to another worker process b) and an intermediary proxy, so you send the requests with FQDN to it and it will return back to the proxy. You can send the dst-uri via some custom headers. This would be like: [ua1] <===> [kamailio main] <===> [kamailio dns] <===> [kamailio main] <===> [ua2] kamailio dns should not do record routing, because requests within dialog should have IP addresses. Cheers, Daniel On 29/07/14 14:31, Igor Potjevlesch wrote: Hello, I’m using Kamailio 4.1 and I’m wondering how to avoid external DNS resolution. I have the following config: dns_cache_init=no use_dns_cache=no dns=no rev_dns=no Even with this config, I have many and many DNS query on SRV _sip for the hostnames set in carrierroute module. These requests are not useful because the A resolution is done by /etc/hosts. Major problem with this, is that when I have a DNS issue or IP transit issue, Kamailio waits for resolution timeout and becomes overloaded. As a consequence, Kamailio can’t treat others SIP requests like REGISTER because he stuck in DNS resolution. Regards, Igor. _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org <mailto:sr-users@lists.sip-router.org> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users -- Daniel-Constantin Mierla - http://www.asipto.com http://twitter.com/#!/miconda <http://twitter.com/#%21/miconda> - http://www.linkedin.com/in/miconda -- Daniel-Constantin Mierla - http://www.asipto.com http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda