diff --git a/docs/configuring-playbook-matrix-rtc.md b/docs/configuring-playbook-matrix-rtc.md
index 919eef9f2..4ea15518f 100644
--- a/docs/configuring-playbook-matrix-rtc.md
+++ b/docs/configuring-playbook-matrix-rtc.md
@@ -36,7 +36,7 @@ matrix_rtc_enabled: true
 
 ## Adjusting firewall rules
 
-In addition to the HTTP/HTTPS ports (which you've already exposed as per the [prerequisites](prerequisites.md) document), you'll also need to open ports required by [LiveKit Server](configuring-playbook-livekit-server.md) as described in its own [Adjusting firewall rules](configuring-playbook-livekit-server.md#adjusting-firewall-rules) section.
+In addition to the HTTP/HTTPS ports and the Matrix Federation port (`8448`, required **even with federation disabled**), which you've already exposed as per the [prerequisites](prerequisites.md) document, you'll also need to open ports required by [LiveKit Server](configuring-playbook-livekit-server.md) as described in its own [Adjusting firewall rules](configuring-playbook-livekit-server.md#adjusting-firewall-rules) section.
 
 ## Fronting the integrated reverse-proxy with another reverse-proxy
 
diff --git a/docs/prerequisites.md b/docs/prerequisites.md
index b9c5f441f..865e2990e 100644
--- a/docs/prerequisites.md
+++ b/docs/prerequisites.md
@@ -57,7 +57,7 @@ We will be using `example.com` as the domain in the following instruction. Pleas
 
   - `80/tcp`: HTTP webserver
   - `443/tcp` and `443/udp`: HTTPS webserver
-  - `8448/tcp` and `8448/udp`: Matrix Federation API HTTPS webserver. Some components like [Matrix User Verification Service](configuring-playbook-user-verification-service.md#open-matrix-federation-port) require this port to be opened **even with federation disabled**.
+  - `8448/tcp` and `8448/udp`: Matrix Federation API HTTPS webserver. Some components like [Matrix User Verification Service](configuring-playbook-user-verification-service.md#open-matrix-federation-port) and the [Matrix RTC stack](configuring-playbook-matrix-rtc.md) require this port to be opened **even with federation disabled**.
   - potentially some other ports, depending on the additional (non-default) services that you enable in the **configuring the playbook** step (later on). Consult each service's documentation page in `docs/` for that.
 
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