diff --git a/fern/call-forwarding.mdx b/fern/call-forwarding.mdx
index e607e841e..81415760a 100644
--- a/fern/call-forwarding.mdx
+++ b/fern/call-forwarding.mdx
@@ -488,3 +488,16 @@ For use cases requiring AI-managed transfers, Vapi supports using assistants to
- Use `"transcript"` for the fastest transfer processing with lowest latency
- Use `"audio"` (default) for comprehensive machine detection including beep detection and other audio cues
- For more details about transfer plans and configuration options, please refer to the [transferCall API documentation](/api-reference/tools/create#request.body.transferCall.destinations.number.transferPlan)
+
+## SIP transfer IP whitelisting
+
+When you transfer calls to a SIP endpoint using the `transferCall` tool with a `"type": "sip"` destination, the SIP `INVITE` originates from Vapi's static SIP signalling IP addresses. If the receiving SIP trunk requires IP whitelisting, add both addresses to your allowlist:
+
+- `44.229.228.186`
+- `44.238.177.138`
+
+These are the same IPs used for all Vapi SIP signalling on ports `5060` (UDP) and `5061` (TLS).
+
+
+For the complete networking reference including RTP port ranges and firewall rules, see [SIP networking and firewall configuration](/advanced/sip/sip-networking).
+
diff --git a/fern/calls/call-dynamic-transfers.mdx b/fern/calls/call-dynamic-transfers.mdx
index 15e62661c..388faabbf 100644
--- a/fern/calls/call-dynamic-transfers.mdx
+++ b/fern/calls/call-dynamic-transfers.mdx
@@ -452,7 +452,7 @@ sequenceDiagram
**SIP transfers:** To transfer to a SIP endpoint, use `"type": "sip"` with `"sipUri"` instead:
-
+
```json
{
"type": "transfer",
@@ -463,6 +463,8 @@ sequenceDiagram
"content": "Transferring your call now."
}
```
+
+ If the receiving SIP trunk requires IP whitelisting, allowlist Vapi's static SIP signalling IPs: `44.229.228.186` and `44.238.177.138`. See [SIP networking and firewall configuration](/advanced/sip/sip-networking) for the full reference.
diff --git a/fern/security-and-privacy/static-ip-addresses.mdx b/fern/security-and-privacy/static-ip-addresses.mdx
index 16731e5ce..cdd0d5c03 100644
--- a/fern/security-and-privacy/static-ip-addresses.mdx
+++ b/fern/security-and-privacy/static-ip-addresses.mdx
@@ -1,13 +1,18 @@
---
title: Static IP addresses
-subtitle: Whitelist Vapi IP addresses
+subtitle: Whitelist Vapi IP addresses
slug: security-and-privacy/static-ip-addresses
---
## Introduction to Vapi static IP addresses
-Vapi supports static IP addresses for outbound HTTP requests. When enabled, all HTTP requests from Vapi to your server will originate from a fixed set of IP addresses, allowing you to configure strict firewall rules and network security policies.
+Vapi uses static IP addresses for two categories of traffic:
+
+- **HTTP webhook requests** -- Outbound HTTP requests from Vapi to your server (must be enabled per server object).
+- **SIP signalling** -- All SIP `INVITE`, `REGISTER`, `BYE`, and other signalling messages, including SIP transfers. These IPs are always static and do not require any opt-in.
+
+Static IPs allow you to configure strict firewall rules and network security policies for both webhook and SIP traffic.
## Why use static IP addresses
@@ -18,17 +23,17 @@ Static IP addresses provide an additional layer of security for your infrastruct
- **Meet compliance requirements** - Satisfy security policies that mandate IP whitelisting
- **Audit traffic sources** - Verify that requests are genuinely from Vapi's infrastructure
-## Vapi's static IP addresses
+## HTTP webhook static IP addresses
When static IP addressing is enabled, all webhook requests from Vapi will originate from the following CIDR block:
- `167.150.224.0/23`
-## Enabling static IP addresses
+### Enabling HTTP static IP addresses
-You can enable static IP addressing through the server object
+You can enable static IP addressing through the server object.
-### Example
+#### Example
```json
{
@@ -41,6 +46,32 @@ You can enable static IP addressing through the server object
Always test static IP configuration in a staging environment before deploying to production to avoid service disruptions.
+## SIP traffic static IP addresses
+
+Vapi uses the following static IP addresses for all SIP signalling traffic, including SIP transfers initiated by the `transferCall` tool. These IPs are always active and do not require any configuration to enable.
+
+| IP address | Port | Protocol |
+| --- | --- | --- |
+| `44.229.228.186` | `5060` (UDP) / `5061` (TLS) | SIP signalling |
+| `44.238.177.138` | `5060` (UDP) / `5061` (TLS) | SIP signalling |
+
+You can also use the DNS hostname `sip.vapi.ai`, which resolves to both addresses.
+
+### When to use these IPs
+
+Allowlist both IP addresses if you:
+
+- **Receive SIP transfers from Vapi** -- When your Vapi assistant transfers calls to a SIP endpoint using the `transferCall` tool, the SIP `INVITE` originates from one of these addresses. Your receiving SIP trunk must allowlist them.
+- **Integrate a SIP trunk with Vapi** -- Your SIP provider's firewall must permit signalling traffic from these addresses for both inbound and outbound calls.
+
+
+Both IP addresses must be allowlisted. Vapi may use either address for any given call. Missing one can cause intermittent call failures or rejected transfers.
+
+
+
+RTP media (voice audio) does **not** use static IPs. For the complete networking reference including RTP port ranges and firewall rules, see [SIP networking and firewall configuration](/advanced/sip/sip-networking).
+
+
## Need help?
-If you have questions about static IP addressing, contact our support team at support@vapi.ai.
\ No newline at end of file
+If you have questions about static IP addressing, contact our support team at support@vapi.ai.
\ No newline at end of file