[Users] Best practice for DNS failover using OpenSER?

Jiri Kuthan jiri at iptel.org
Fri Jan 12 18:10:00 CET 2007

At 17:36 11/01/2007, Christian Schlatter wrote:
>Kerker Staffan wrote:
>>Now, if I disable one of the Gateways, I hang every second call. OpenSER does not
>>try the second A record address if the first doesn't answer. How can I solve
>>this? Shouldn't OpenSER fail over to the second A record listed in the NAPTR => SRV
>>resolving? Or will OpenSER continue to resend all SIP INVITES until timers fire? Would
>>it help if the proxy recieved an ICMP port/destination unreachable from the network? Is
>>there anyway to get around this? In the other direction, from POTS to sip, the PGW2200
>>nicely switches over to the second of my two OpenSER servers if I shut one of them down. These servers have the same DNS entries (but for another SIP domain, NAPTR => SRV => 2x A record).
>Yes, OpenSER or for that matter every transaction stateful proxy should do RFC 3263 based fail-over. But as you can imagine this is pretty complex to implement and that's why openser does not support it yet, it is listed on the development roadmap. The newest release of SER does support DNS failover.

Indeed. SER does so. See the doc at

Jiri Kuthan            http://iptel.org/~jiri/  

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