Setting up a Telnyx SIP connection

See also

Sources

1. 1
   By default, Telnyx AnchorSite selection measures round-trip time with ICMP pings and anchors media at the lowest-latency PoP; the API value is Latency.

   Getting Started with Telnyx (SIP network reference) · AnchorSite · Checked 2026-10-14
2. 2
   Telnyx recommends manually pinning the AnchorSite when the endpoint does not answer ICMP or its media IP is in a different region from its signaling IP.

   Getting Started with Telnyx (SIP network reference) · AnchorSite · Checked 2026-10-14
3. 3
   A Telnyx SIP connection's outbound ANI override can apply to all calls, to normal calls only, or to emergency calls only (ani_override_type always, normal or emergency; default always).

   Create an IP connection · outbound.ani_override_type · Checked 2026-10-14
4. 4
   Telnyx developer documentation lists five SIP trunking authentication methods: credential-based, IP + Token, IP + Tech Prefix, IP + P-Charge-Info, and FQDN.

   SIP Authentication Methods · Methods · Checked 2026-10-14
5. 5
   Per the Telnyx failover documentation, the Canada signaling IPs are 193.108.220.10 (primary) and 193.108.220.25 (secondary).disputed

   Failover and Retries · Failover Overview table, Canada row · Checked 2026-10-14
6. 6
   Per sip.telnyx.com, the Telnyx Canada SIP proxy is sip.telnyx.ca at 192.76.120.31 and 64.16.250.13.disputed

   Getting Started with Telnyx (SIP network reference) · SIP Signaling Addresses, Canada row · Checked 2026-10-14
7. 7
   Telnyx SIP supports the audio codecs G.711 mu-law, G.711 A-law, G.729, G.722, Opus and AMR-WB, plus H.264 and VP8 video, with 20 ms packetization.

   Getting Started with Telnyx (SIP network reference) · Codecs · Checked 2026-10-14
8. 8
   default_on_hold_comfort_noise_enabled defaults to false on Telnyx credential connections; without it, the PBX must send comfort noise or hold music to avoid an RTP timeout.

   Create a credential connection · default_on_hold_comfort_noise_enabled · Checked 2026-10-14
9. 9
   Telnyx limits outbound calls from the same IP address or SIP username to 20 calls per second.

   Getting Started with Telnyx (SIP network reference) · SIP Signaling Addresses (rate limit note) · Checked 2026-10-14
10. 10
    For a Credentials SIP connection, Telnyx auto-generates the username and password. They can be changed in the Authentication & Routing Configuration section.

    SIP Connection: Types · Credentials · Checked 2026-10-14
11. 11
    Telnyx recommends a credential-based SIP connection when the customer has a dynamic public IP address.

    SIP Connection: Types · Credentials · Checked 2026-10-14
12. 12
    A Telnyx credential connection password must be 8 to 128 characters long.

    Create a credential connection · password · Checked 2026-10-14
13. 13
    A Telnyx credential connection user_name must be 4 to 32 alphanumeric characters, and at least one of the first five characters must be a letter.

    Create a credential connection · user_name · Checked 2026-10-14
14. 14
    A Telnyx credential connection's default inbound codec order is G722, G711U, G711A, G729, OPUS, H.264, and OPUS and H.264 require TCP or TLS transport.

    Create a credential connection · inbound.codecs · Checked 2026-10-14
15. 15
    The default inbound DNIS number format on a Telnyx SIP connection is E.164 without the leading plus; +E.164, National and SIP Username are the alternatives.

    SIP Connection: Number Formats · number format options; default · Checked 2026-10-14
16. 16
    Telnyx regional SIP FQDNs publish A, SRV and NAPTR records. The A record resolves only to IP 1, while SRV and NAPTR round-robin across both IPs and advertise transports and ports.

    Getting Started with Telnyx (SIP network reference) · SIP Signaling Addresses, DNS notes · Checked 2026-10-14
17. 17
    Per the Telnyx failover documentation, the EU signaling IPs are 5.172.39.10 (primary) and 5.172.39.25 (secondary), and the EU domain is sip-eu.telnyx.com.disputed

    Failover and Retries · Failover Overview table, EU row; DNS Configuration · Checked 2026-10-14
18. 18
    Per sip.telnyx.com, the Telnyx Europe SIP proxy is sip.telnyx.eu at 185.246.41.140 and 185.246.41.141.disputed

    Getting Started with Telnyx (SIP network reference) · SIP Signaling Addresses, Europe row · Checked 2026-10-14
19. 19
    When delivering calls, Telnyx sends the INVITE from signaling IP1, then retries from IP2; with multiple routes it tries all routes via IP1 in order, then all via IP2.

    Failover and Retries · Failover and Retry Behavior · Checked 2026-10-14
20. 20
    Telnyx fails over to the next route on 408, 480, 503, 504 or a transport error, but treats 180, 200, 404, 486 and 603 as final, with no failover.

    Failover and Retries · SIP Responses That Trigger Failover table · Checked 2026-10-14
21. 21
    If all SIP routes fail, a Telnyx connection can forward the call to a PSTN number via call_forwarding with forwarding_type on_failure.

    Failover and Retries · Failover and Retry Behavior; Configuration · Checked 2026-10-14
22. 22
    Telnyx FQDN authentication covers inbound routing by hostname only; outbound calls on an FQDN connection authenticate by credentials or by IP address.

    SIP Authentication Methods · FQDN authentication · Checked 2026-10-14
23. 23
    The Telnyx IP connection API field outbound.ip_authentication_method selects between tech-prefix/P-Charge-Info and token authentication; tech-prefix/P-Charge-Info is the default.

    Create an IP connection · outbound.ip_authentication_method · Checked 2026-10-14
24. 24
    The Telnyx authentication comparison marks IP + Tech Prefix, IP + Token, IP + P-Charge-Info and FQDN + IP as unsupported for dynamic IPs; they need a static IP.

    SIP Authentication Methods · Comparison table, Dynamic IP column · Checked 2026-10-14
25. 25
    Telnyx warns that an IP Address connection on a non-static IP will be unable to make or receive calls once the IP changes.

    SIP Connection: Types · IP Address · Checked 2026-10-14
26. 26
    With no outbound localization country set on a Telnyx SIP connection, numbers are validated as US numbers, and a failed validation returns 404 invalid destination.

    SIP Connection: Inbound & Outbound Settings · Outbound, Localization · Checked 2026-10-14
27. 27
    Telnyx developer documentation names sip.telnyx.com as the source for current SIP signaling addresses, media IP ranges, supported codecs and regional FQDNs.

    IP Whitelisting · SIP Signaling and Media · Checked 2026-10-14
28. 28
    Outbound calls beyond a Telnyx SIP connection's outbound channel limit are rejected with a 403 channel limit reached response.

    SIP Connection: Inbound & Outbound Settings · Outbound, Channel limit · Checked 2026-10-14
29. 29
    An Outbound Voice Profile channel limit caps concurrent outbound channels per profile, with each active call using one channel.

    Outbound Voice Profiles · channel limit · Checked 2026-10-14
30. 30
    Outbound Voice Profiles enable destinations by region or by country, out of 255 destinations in 10 regions, and many destinations require Level 2 verification first.

    Outbound Voice Profiles · destination enablement · Checked 2026-10-14
31. 31
    A Telnyx Outbound Voice Profile governs routing, billing and rate limits for outbound SIP calls on the connections associated with it.

    Outbound Voice Profiles · overview; profile components · Checked 2026-10-14
32. 32
    A Telnyx SIP connection without an associated Outbound Voice Profile probably cannot place outbound calls, as the docs present the profile as the means of routing outbound calls.inferred

    SIP Trunking: Get Started · Outbound Voice Profiles · Checked 2026-10-14
33. 33
    A Telnyx Outbound Voice Profile daily spend limit applies per day per connection and resets at 00:00:00 UTC.

    Outbound Voice Profiles · daily spend limit · Checked 2026-10-14
34. 34
    For Telnyx primary accounts created on or after 2026-09-08, the API masks connection passwords as ******** in responses, returning them in full only on create.

    Create a credential connection · password (response schema) · Checked 2026-10-14
35. 35
    With IP + P-Charge-Info authentication, the number in the P-Charge-Info header must be in E.164 format and assigned to the connection.

    SIP Authentication Methods · P-Charge-Info authentication · Checked 2026-10-14
36. 36
    Telnyx learns the customer media IP from early RTP packets and re-targets media if it differs from the SDP; Disable RTP Auto Adjust turns this off.

    Getting Started with Telnyx (SIP network reference) · Media Handling · Checked 2026-10-14
37. 37
    Telnyx RTP and SRTP media uses UDP ports 16384 to 32768.

    Getting Started with Telnyx (SIP network reference) · Media · Checked 2026-10-14
38. 38
    Telnyx tech prefix, X-Telnyx-Token and P-Charge-Info authentication exist to tell apart multiple SIP connections that share one source IP address.

    IP Authentication with Tech Prefix · purpose; alternatives for shared IPs · Checked 2026-10-14
39. 39
    Telnyx SIP signaling uses UDP and TCP port 5060 and TLS on TCP port 5061.

    Getting Started with Telnyx (SIP network reference) · Ports and Transports · Checked 2026-10-14
40. 40
    A Telnyx credential connection's sip_uri_calling_preference is disabled, unrestricted (SIP URI calls from anyone) or internal (only calls from connections on the same account).

    Create a credential connection · sip_uri_calling_preference · Checked 2026-10-14
41. 41
    Telnyx lists AEAD_AES_256_GCM_8 as its default preferred SRTP crypto suite and AES_CM_128_HMAC_SHA1_80 as also supported.

    Getting Started with Telnyx (SIP network reference) · Encryption · Checked 2026-10-14
42. 42
    Telnyx connection APIs do not allow encrypted_media (SRTP) to be set when the connection's transport_protocol is TLS.

    Create an IP connection · encrypted_media · Checked 2026-10-14
43. 43
    On Telnyx IP connections, inbound SIP subdomain calls do not allow TLS; receipt is limited to only_my_connections or opened to from_anyone.

    Create an IP connection · inbound.sip_subdomain; inbound.sip_subdomain_receive_settings · Checked 2026-10-14
44. 44
    The Telnyx IP connection API schema gives outbound.t38_reinvite_source the default 'customer', out of telnyx, customer, disabled, passthru, caller-passthru and callee-passthru.disputed

    Create an IP connection · outbound.t38_reinvite_source · Checked 2026-10-14
45. 45
    According to the Telnyx help article, the connection's outbound 'T.38 Re-invite Initiated By' setting defaults to Telnyx.disputed

    SIP Connection: Inbound & Outbound Settings · Outbound, (FAX Settings) T.38 Re-invite Initiated By · Checked 2026-10-14
46. 46
    For inbound fax, Telnyx expects a T.38 re-INVITE by default and keeps the call on G.711 if none arrives; this is disabled per number.

    Getting Started with Telnyx (SIP network reference) · FAX · Checked 2026-10-14
47. 47
    Enabling microsoft_teams_sbc on a Telnyx FQDN connection automatically creates a *.mstsbc.telnyx.tech FQDN.

    Create an FQDN connection · microsoft_teams_sbc · Checked 2026-10-14
48. 48
    A missing or incorrect tech prefix on a Telnyx tech-prefix connection fails the call with 407 Proxy Authentication Required.

    IP Authentication with Tech Prefix · error response section · Checked 2026-10-14
49. 49
    Telnyx developer documentation says the tech prefix value is assigned by Telnyx and shown in the connection settings, while the customer enables it via outbound.tech_prefix_enabled.

    IP Authentication with Tech Prefix · assignment; API fields · Checked 2026-10-14
50. 50
    A Telnyx tech prefix is a 4-digit number the PBX prepends to the destination, for example 1234 plus +18005678912 is dialled as 123418005678912.

    IP Authentication with Tech Prefix · dial string format and example · Checked 2026-10-14
51. 51
    Because the IP connection API exposes a writable outbound.tech_prefix field (exactly 4 digits, default empty), a customer may be able to set the prefix value directly, despite docs saying Telnyx assigns it.inferred

    Create an IP connection · outbound.tech_prefix · Checked 2026-10-14
52. 52
    During 2026, Telnyx is migrating its SIP proxy TLS certificates from Sectigo/DigiCert to Let's Encrypt, region by region.

    Getting Started with Telnyx (SIP network reference) · Encryption · Checked 2026-10-14
53. 53
    Telnyx SIP over TLS on sip.telnyx.com:5061 does not accept TLS 1.0 or 1.1; endpoints must use TLS 1.2 or 1.3.

    Getting Started with Telnyx (SIP network reference) · Encryption · Checked 2026-10-14
54. 54
    With token authentication the PBX must send the X-Telnyx-Token header in every outbound INVITE; calls whose source IP matches but whose token is missing or wrong are rejected.

    IP Authentication Token · where to send it; behaviour when token is missing · Checked 2026-10-14
55. 55
    A Telnyx X-Telnyx-Token value must be 12 to 48 characters of letters, digits and hyphens, and must be globally unique across all Telnyx connections.

    IP Authentication Token · token format requirements · Checked 2026-10-14
56. 56
    The transport_protocol of a Telnyx IP or FQDN connection is UDP, TCP or TLS, and defaults to UDP.

    Create an IP connection · transport_protocol · Checked 2026-10-14
57. 57
    In a Telnyx UAC connection (SIP Attach), the roles are reversed: Telnyx registers to the customer PBX as an extension, and the PBX is the registrar.

    How to Configure SIP Attach using a UAC Connection · What UAC / SIP Attach is · Checked 2026-10-14
58. 58
    The Telnyx US UAC (SIP Attach) IP is 192.76.120.14 and must be allowlisted on the PBX; Telnyx uses the same IP for UAC signaling and media.

    How to Configure SIP Attach using a UAC Connection · Allowlisting UAC IPs · Checked 2026-10-14
59. 59
    The Telnyx US SIP proxy FQDN sip.telnyx.com uses two signaling IPs, 192.76.120.10 and 64.16.250.10.

    Getting Started with Telnyx (SIP network reference) · SIP Signaling Addresses, US row · Checked 2026-10-14

Documents

Cite this page

WarmTransfer. (2026, October 14). Setting up a Telnyx SIP connection. WarmTransfer. https://warmtransfer.net/knowledge/telnyx-sip-trunk-setup

@misc{warmtransfer-telnyx-sip-trunk-setup,
  title  = {Setting up a Telnyx SIP connection},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/telnyx-sip-trunk-setup},
  note   = {Verified 2026-10-14}
}