On Tue, 26 Feb 2019 12:39:50 +0000 "STR ." <stry...@hotmail.com> wrote:
> I have Fiber to our apartment complex basement, from there Cat6 runs to > each apartment. The ISP/apartment service provider suggests an MTU of > 1448, which I set for the PPPoE interface on my OpenWRT router. It could be that your ISP meant this as the pre-PPPoE MTU, so 1448 on ethX link, but 1440 inside PPPoE. > I read > https://lists.zx2c4.com/pipermail/wireguard/2017-December/002201.html > which comes to (assuming 1500 byte MTU) to 60 bytes (IPv6) to 80 bytes less > to account for Wireguard protocol overhead. > > Using this info, I tried an MTU of both (1448-80=1368) and (1448- > 60=1388). > As my ISP assigns only IPv4, I expected an MTU of 1388 to work, which I > set on the Wireguard interface in OpenWRT. > > However, when set to 1388, almost everything works except any Google > related sites like Maps, Gmail, YT etc. > When set to 1368, everything works and it's the way I have it setup > right now. Try 1380 for a bit. > What am I missing here? > Why won't Google sites load via my WG VPN when the MTU is set to 1388? > > If it helps, I host the WG server on Google's cloud platform and was > informed that GCP has an MTU of 1460 bytes. Are you setting the same (lower of the two maximums) MTU on both ends of the wireguard tunnel? (You should) -- With respect, Roman _______________________________________________ WireGuard mailing list WireGuard@lists.zx2c4.com https://lists.zx2c4.com/mailman/listinfo/wireguard