On Wed, 4 Sep 2024 09:22:08 +0200, Antonio Quartulli wrote ... > That practically means that QUIC is equally broken everytime macOS is > used behind a router with a smaller MTU (like the PPPoE case mentioned > by Gert). > > Are we truly sure about these statement?
In fact, all UDP applications are extremely conservative about maximal packet sizes: e.g. QUIC never uses packets larger than 1385 bytes, MPEG-TS over RTP/UDP uses max. 1328 bytes etc. Thus PPPoE is no problem, as it provides 1492 byte MTU. Also iPhone's/iPad's safety-belt default MTU 1450 in 5G/LTE networks still works. However mssfix=1400 in OpenVPN might result in max. usable packet of e.g. 1376 bytes, which is 9 bytes less than needed for QUIC. Combined with UDP packet blackholing, that's a serious problem - and much better approach would be to lower tun-mtu, if you want to completely avoid fragmentation for all protocols. With kind regards, MD _______________________________________________ Openvpn-users mailing list Openvpn-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openvpn-users
