diff --git a/common/chapters/port_numbers.adoc b/common/chapters/port_numbers.adoc
index 3efa179..6309c66 100644
--- a/common/chapters/port_numbers.adoc
+++ b/common/chapters/port_numbers.adoc
@@ -40,6 +40,7 @@ which protocol / interface.
 |TCP|4260|telnet (VTY)|osmo-ggsn
 |TCP|4261|telnet (VTY)|osmo-hnbgw
 |TCP|4262|Control Interface|osmo-hnbgw
+|TCP|4263|Control Interface|osmo-gbproxy
 |UDP|4729|GSMTAP|Almost every osmocom project
 |TCP|5000|A/IP|osmo-bsc, osmo-bsc_nat
 |UDP|2427|GSMTAP|osmo-pcu, osmo-bts