diff --git a/common/chapters/port_numbers.adoc b/common/chapters/port_numbers.adoc
index f2166ab..a5b9036 100644
--- a/common/chapters/port_numbers.adoc
+++ b/common/chapters/port_numbers.adoc
@@ -43,6 +43,7 @@ which protocol / interface.
 |TCP|4263|Control Interface|osmo-gbproxy
 |TCP|4264|telnet (VTY)|osmo-cbc
 |TCP|4265|Control Interface|osmo-cbc
+|TCP|4266|D-GSM MS Lookup: mDNS serve|osmo-hlr
 |TCP|4267|Control Interface|osmo-mgw
 |UDP|4729|GSMTAP|Almost every osmocom project
 |TCP|5000|A/IP|osmo-bsc, osmo-bsc_nat