Bug #43683 for bind9-public: TCP segment handling issue?

In message <rt-4.2.8-98277-1479467836-1082.43683-3-0@isc.org>, "Ray Bellis via RT" writes: > Via kato@wide.ac.jp: > > bind-9.11.0-p1 seems to me that it applys TCP_MAXSEG to 1220byte even > in IPv4, resulting TCP transmission a little bit less efficient. At > around line 3698 of lib/isc/unix/socket.c, the code should be executed > only if protocol family is AF_INET6: > > if (NEWCONNSOCK(dev)->pf == AF_INET6) { > use_min_mtu(NEWCONNSOCK(dev)); > set_tcp_maxseg(NEWCONNSOCK(dev), 1280 - 20 - 40); > } > > > This relates to the survey done by Geoff Huston and reported on his blog > earlier this week. And there is nothing wrong with this. We really don't want PMTUD to happen over IPv4 or IPv6. Setting the max seg to 1220 avoids triggering PMTUD for IPv6 over IPv4 and IPv4 over IPv6. If anything the pf test should be removed. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org

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