diff --git a/machines/prattle/default.nix b/machines/prattle/default.nix
index 9447014..b9dd21a 100644
--- a/machines/prattle/default.nix
+++ b/machines/prattle/default.nix
@@ -200,6 +200,7 @@
     allowedUDPPorts = [
       137
       138 # Samba NetBIOS
+      443 # HTTP/3: caddy advertises h3 whether or not this is open
     ];
     logRefusedConnections = false;
     rejectPackets = true;
diff --git a/machines/terebithia/default.nix b/machines/terebithia/default.nix
index 3598a69..3ba8c13 100644
--- a/machines/terebithia/default.nix
+++ b/machines/terebithia/default.nix
@@ -275,6 +275,7 @@
     ];
     allowedUDPPorts = [
       28869 # Minecraft voice chat
+      443 # HTTP/3: caddy advertises h3 whether or not this is open
     ];
     logRefusedConnections = false;
     rejectPackets = true;