From: Ondřej Surý Date: Wed, 6 May 2026 13:09:09 +0000 (+0200) Subject: [9.20] fix: usr: Implement seamless outgoing TCP connection reuse X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb117e16b96f4892755c073d8888e52f8317bf3b;p=thirdparty%2Fbind9.git [9.20] fix: usr: Implement seamless outgoing TCP connection reuse The resolver can and will reuse outgoing TCP connections to the same host, as recommended by RFC 7766. This prevents a whole class of attacks that abuse the fact that establishing a TCP connection is expensive and it is fairly easy to deplete the outgoing TCP ports by putting them into TIME_WAIT state. The number of pipelined queries per connection is capped at 256 to limit the impact of a connection drop. Backport of MR !11845 Merge branch 'backport-3741-reuse-tcp-connections-9.20' into 'bind-9.20' See merge request isc-projects/bind9!11846 --- eb117e16b96f4892755c073d8888e52f8317bf3b