SIP Connection Credential

What This Credential Is Used For

SIP Connection is the credential type named sipPbxExternal.

It is used in two public places:

• SIP PBX Trigger in Trunk Event mode
• SIP PBX -> Dial -> Make Call -> Direct mode

It is not selected for Dial -> Trunk mode. In trunk mode, the dial action references an already active trunk trigger by ref.

Field Reference

Field	Required	Purpose
SIP Server	Yes	Remote SIP server hostname or IP, without a sip: prefix
Proxy Server	No	Optional outbound SIP proxy hostname or IP
Realm	No	SIP authentication realm override
Port	Yes	Remote SIP server port
Transport	Yes	SIP transport. The current UI exposes UDP
Username	No	SIP authentication username
Password	No	SIP authentication password
Local Bind IP	No	Local interface override on the n8n host
Local Bind Port	No	Local source port override
Use STUN	No	Enables STUN-based public address discovery
STUN Server	No	STUN server hostname
STUN Port	No	STUN server port
Public Domain	No	Public SIP host advertised in Contact and Via for NAT scenarios

How To Fill It Correctly

SIP Server

Enter only the host or IP.

Correct:

• pbx.example.com
• 203.0.113.10

Do not enter:

• sip:pbx.example.com
• a full SIP URI with user information

Proxy Server

Use this only when your provider requires a separate outbound SIP proxy.

Realm

Leave it blank unless:

• your provider explicitly requires a custom realm
• the default challenge realm does not match the username/password flow you need

Username and Password

These are optional at the credential level because not every SIP path needs registration or digest auth in the same way. In practice:

• trunk registration usually needs them
• direct outbound dialing may need them
• some trusted internal SIP environments may not

Typical Usage Patterns

Trunk trigger

Use this credential when a workflow should:

• register against a carrier or upstream PBX
• receive inbound calls on that trunk
• originate trunk-based outbound calls through a known Trunk Ref

Direct dialing

Use this credential when a workflow should:

• originate a call without creating a separate trunk trigger
• call a SIP destination directly from one action node

Important Separation of Responsibilities

The destination number or user is not stored in the credential.

The credential stores:

• where to send SIP signaling
• which authentication to use
• how to bind locally

The action node stores:

• the number or user to dial
• the caller identity
• call strategy and custom headers

Practical Notes

• Transport is currently exposed as UDP in the node UI.
• Relative media paths and recording paths are unrelated to this credential.
• If you use NAT, Public Domain and STUN settings can matter more than a SIP password issue.