Route SIP Through a WireGuard Interface - Telnyx

With enable_sip_trunking set to true, a WireGuard Interface carries its peers’ SIP traffic to Telnyx inside the tunnel. The peer configuration adds the Telnyx SIP prefixes to AllowedIPs, so traffic to sip.telnyx.com and sip.telnyx.eu goes via the interface instead of the peer’s default route.

Setup

Create the interface with enable_sip_trunking set to true. Interfaces have no update operation, so set the flag at creation:

{
  "network_id": "91446ee3-9f6a-49ed-8d9b-1bd3e1529324",
  "name": "wg-sip-ashburn",
  "region_code": "ashburn-va",
  "enable_sip_trunking": true
}

Wait for provisioned, create a peer, and retrieve its configuration, as in the Quick Start. AllowedIPs now lists the Telnyx SIP prefixes after the interface subnet:
[Peer] PublicKey = jSSaLXXVEzYUM8N8IM+65YuuScL+Sf2DytZCdLhFSGo= AllowedIPs = 172.27.0.0/24, 192.76.120.10/32, 185.246.41.140/32, ... Endpoint = 64.16.243.15:5016 PersistentKeepalive = 1
The list above is abbreviated. Load the configuration as returned.

Verify

The first hop to sip.telnyx.com is the interface address:

user@localhost ~ % traceroute sip.telnyx.com
traceroute to sip.telnyx.com (192.76.120.10), 64 hops max, 40 byte packets
 1  172.27.0.1 (172.27.0.1)  6.708 ms  7.726 ms  7.133 ms