diff --git a/fern/advanced/sip/sip-trunk.mdx b/fern/advanced/sip/sip-trunk.mdx index 0e40db6fb..bebb3367f 100644 --- a/fern/advanced/sip/sip-trunk.mdx +++ b/fern/advanced/sip/sip-trunk.mdx @@ -8,12 +8,20 @@ SIP trunking replaces traditional phone lines with a virtual connection over the ## Network requirements -To allow SIP signaling and media between Vapi and your SIP provider, you must allowlist the following IP addresses: +### SIP signaling + +To allow SIP signaling between Vapi and your SIP provider, you must allowlist the following IP addresses: - 44.229.228.186/32 - 44.238.177.138/32 -These IPs are used exclusively for SIP traffic. +These IPs are used exclusively for **SIP signaling traffic only** (call setup, teardown, and control messages). + +### RTP media + + +**RTP media traffic does not currently have a static set of IP addresses that can be whitelisted.** RTP media (the actual audio/video streams) may originate from dynamic IP addresses. If your firewall requires specific IP allowlisting for RTP traffic, please contact Vapi support to discuss your requirements. + We generally don't recommend IP-based authentication for SIP trunks as it can lead to routing issues. Since our servers are shared by many customers, if your telephony provider has multiple customers using IP-based authentication, calls may be routed incorrectly. IP-based authentication works reliably only when your SIP provider offers a unique termination URI or a dedicated SIP server for each customer, as is the case with Plivo and Twilio integrations. @@ -130,5 +138,3 @@ Note: Certain providers require phone numbers to be formatted in the proper E.16 You might need to enable SIP REFER in your SIP provider to allow this. - -