BIND 9.16.25 "file descriptor exceeds limit" messages

[Tony Finch]

Anand Buddhdev <anandb at ripe.net> wrote:
>
> The server has many IP addresses. In named.conf, there are 129 IPv6 addresses
> in the "listen-on-v6" option and 128 IPv4 addresses in the "listen-on" option.
> The server begins running, but then repeatedly emits this log:
>
> general: error: socket: file descriptor exceeds limit (46474/21000)

Hmm, (128+129)*88*2 == 45232, (2 == UDP + TCP) so the big number looks
plausible.

The 21000 limit comes from a hardcoded value for ISC_SOCKET_MAXSOCKETS.

You can adjust -U (number of listeners) on the command line to avoid
hitting the fixed MAXSOCKETS limit, and leave -n (max sockets) unset, at
its default. You can also set ISC_SOCKET_MAXSOCKETS at build time, if you
can work out how to wrangle the build system :-)

Tony.
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