Due to load balancing, redundancy, and regional restrictions, Twilio is unable to send all of your SIP traffic over a particular IP address. We recommend Elastic SIP Trunking customers allow ALL of our regional signaling and IP addresses for maximum compatibility.

• You can find the full list of our SIP signaling and media IP addresses on the SIP Trunk Networking Information page in Console.
• For further information to help you configure your infrastructure for your Twilio Elastic SIP Trunk, please see our SIP Trunking interconnection guides.

However you could specify the geographic edge from which Twilio will send the originating SIP traffic towards your communication infrastructure, you must include the edge parameter in your Origination SIP URI. For example, if the edge=dublin parameter is included in your Origination SIP URI, Twilio will send the SIP traffic from the Europe Ireland edge location:

• sip:anniebp@172.56.42.132;edge=dublin

If the edge parameter is not specified or is incorrect, Twilio will send the Originating SIP traffic from the edge location where the incoming PSTN call comes in.

Note: You must make sure you allow the IP Addresses of the Twilio edge location for SIP signalling and RTP media traffic.