This problem is neither new nor specific to Yahoo or IPv6 and is usually referred as "blackhole router". ICMPv4 "Fragmentation Needed" (type 3 code4) / ICMPv6 "Packet to Big" (type 2) *are required* for path MTU discovery and should never be filtered. The only reason it doesn't strike you with different servers is it's highly recommended for public server to set MaxMTU lower than 1500 (typically 1400 or so, or more exactly TCP MSS is usually set to corresponding value), because there is a lot of users with misconfigured routers and firewall.
18.11.2016 22:58, Carl Byington пишет: > https://login.yahoo.com > > If you have IPv6 connectivity thru a tunnel, with a smaller MTU, that > will fail. With a 1500 byte MTU, it works. The TCP handshake works - it > then hangs during the TLS handshake which sends full size packets. > > echo -e 'GET / HTTP/1.0\n' | \ > openssl s_client -servername login.yahoo.com -ign_eof -connect \ > '[2001:4998:c:e33::50]:443' > > Please stop filtering icmpv6 packets going to your servers. > > > > > > _______________________________________________ > mailop mailing list > [email protected] > https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop -- Vladimir Dubrovin @Mail.Ru
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