What are SIP DNS SRV records?

The SRV RR allows administrators to use several servers for a single domain, to move services from host to host with little fuss, and to designate some hosts as primary servers for a service and others as backups

This great blog post by Andres Brownworth walks you thru the details of using SIP DNS SRV records and why its used.

How to configure SIP DNS SRV records in TelecomsXChange

TelecomsXChange is now fully compatible to route calls to other highly available cloud communications platforms over DNS SRV Records, setting it up is very simple. here is an example of how to setup outbound calls to a SIP DNS SRV record on Restcomm Cloud platform.

1- Login to your seller account on TelecomsXChange

2- Click on Routes menu

3- Add new route

4- Enter the SIP DNS SRV record in the IP:Port field : e.g  _sip_udp_{organization}




5- Update Settings

13 Mar 20:51:28.135/GLOBAL/b2bua: RECEIVED message from
SIP/2.0 569 Problem to setup services

Via: SIP/2.0/UDP;branch=z9hG4bK1363e76a73f53f9d8e78070177c40fcc;rport=5061;received=
CSeq: 200 INVITE
Call-ID: 9c3b3385-c074-1237-0a91-0cc47ae18bfa-rtest-b2b_1
From: <sip:bob@>;tag=a1a08893e1fa8d3e29e2bd199de3f449
Server: Restcomm 8.4.0-227
Contact: <sip:;transport=tcp>
X-RestComm-AccountSid: ACd1533beeccfd92089b8c95c55443xxxx
X-RestComm-CallSid: IDa721a1e38bc040c08625cb9617968482-CA0011837cf97842488c8ccf182e9ae9bc
Content-Length: 0

As you can see in the SIP log, TelecomsXChange first resolved the IP address  from the DNS SRV Record and passed the domain in the  SIP request URI (To:<>).

Restcomm Cloud received the call for the To: number which is registered on their system and the call was successfully routed to the RVD Application.



Use cases

There aren’t many SIP soft switches or SBC (Session Border Controllers) that support routing SIP over DNS SRV Records, if you’re using an outdated or a black box that does not support this feature, you may you use TelecomsXChange platform as a bridge to Cloud Communication Platforms like Restcomm.

You can now do things like, CPaaS Enable  your DID Numbers block on Restcomm Cloud via TelecomsXChange platform without having to make any changes in your existing SIP Stack.

This also enabled integrate your existing IP Networks with CPaaS (Communication Platform as a Service) applications with ease, maybe things like calling a customer from your IP-PBX and offload recording and SMS follow up to the Restcomm Cloud.


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