Support for addn_hosts in dnsmasq on Orbi RBR50

In case anyone is interested in a bit of an extended hack, here's a script that you can use (using the expect utility in Linux) to log into the Orbi and configure dnsmasq programatically. This way when the Orbi reboots, you simply re-run the script.

It allows both usage of /tmp/dhcpd_hostlist which uses the name each client identifies with (which often can be unset) but it also allows you to put a hosts file on a FAT32 formatted USB stick and put that USB stick into the Orbi Router which on the RBR50 is accessible via /mnt/sda1

Script:

#!/usr/bin/expect

set addn_hosts "addn-hosts=/mnt/sda1/hosts\naddn-hosts=/tmp/dhcpd_hostlist\n"

set host "192.168.1.1"
set user "admin"
set password "********************"
set timeout 20

spawn telnet $host
expect "login:" 
send "$user\n"
expect "Password:"
send "$password\n"

send "grep -qF addn-hosts /etc/dnsmasq.conf || (echo \'$addn_hosts\' >> /etc/dnsmasq.conf && echo 'addn-hosts added')\n"
send "pidof dnsmasq\n"
send "kill \$(pidof dnsmasq)\n"
send "/usr/sbin/dnsmasq --except-interface=lo -r /tmp/resolv.conf\n"
send "pidof dnsmasq\n"

If you don't want to supply a separate hosts file (in the format of ip_addr hostname, with each mapping being a separate line), then you can just remove the addn_hosts=/mnt/sda1/hosts from the addn_hosts variable in the script. This will make it so the only hosts file used is /tmp/dhcpd_hostlist

But if you format a USB drive as FAT32 (or vfat) and put a hosts file on it, you can then arbitrarily configure the Orbi DNS server with whatever local DNS names you want.

Hope this helps someone out.