/etc/boinc-client/remote_hosts.cfg is in boinc-client 7.4.23+dfsg-1+deb8u1.
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 | # This file contains a list of hostnames or IP addresses (one per line)
# of remote hosts, that are allowed to connect and to control the local
# BOINC core client via GUI RPCs.
# Lines beginning with a # or a ; are treated like comments and will be
# ignored.
#
#host.example.com
#192.168.0.180
|