diff --git a/nixbld-etc-nixos/configuration.nix b/nixbld-etc-nixos/configuration.nix
index df84b846..da585b3b 100644
--- a/nixbld-etc-nixos/configuration.nix
+++ b/nixbld-etc-nixos/configuration.nix
@@ -180,7 +180,7 @@ in
         iptables -w -A FORWARD -j block-insecure-devices
 
         iptables -w -N pccw-sucks
-        iptables -A pccw-sucks -o ${netifSit} -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1360
+        iptables -A pccw-sucks -o ${netifSit} -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1440
         iptables -A pccw-sucks -o ${netifAlt} -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1380
         iptables -w -A FORWARD -j pccw-sucks
       '';