/etc/bindresvport.blacklist is in libc-bin 2.19-18+deb8u10.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | #
# This file contains a list of port numbers between 600 and 1024,
# which should not be used by bindresvport. bindresvport is mostly
# called by RPC services. This mostly solves the problem, that a
# RPC service uses a well known port of another service.
#
631 # cups
636 # ldaps
655 # tinc
774 # rpasswd
783 # spamd
873 # rsync
921 # lwresd
993 # imaps
995 # pops
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