diff --git a/config.cfg b/config.cfg
index 5cb3eaa..34d15f5 100644
--- a/config.cfg
+++ b/config.cfg
@@ -32,6 +32,9 @@ strongswan_network: 10.19.48.0/24
 strongswan_network_ipv6: 'fd9d:bc11:4020::/48'
 
 # Deploy WireGuard
+# WireGuard will listen on 51820/UDP. You might need to change to another port
+# if your network blocks this one. Be aware that 53/UDP (DNS) is blocked on some
+# mobile data networks.
 wireguard_enabled: true
 wireguard_port: 51820
 # If you're behind NAT or a firewall and you want to receive incoming connections long after network traffic has gone silent.