Parental control

Because you can't let the kids on YouTube 24/7 and some games are really addictive :)

The router must run OpenWRT or DD-WRT.

The kids devices must be assigned IP's from a certain range, let's say 192.168.1.128/28 by adding some lines similar to the following one into Additional Dnsmasq Options:
dhcp-host=set:red,AA:BB:CC:00:DD:22,kids-tv,192.168.1.130,43200m


A series of scripts must be put in /jffs/ and called by a cron job:

cat add_fw
#!/bin/sh
iptables -I FORWARD 1 -s 192.168.1.128/28 -j DROP
iptables -I FORWARD 2 -s 192.168.1.128/28 -m conntrack -j DROP --ctstate RELATED,ESTABLISHED

cat del_fw

#!/bin/sh

iptables -D FORWARD -s 192.168.1.128/28 -j DROP

iptables -D FORWARD -s 192.168.1.128/28 -m conntrack -j DROP --ctstate RELATED,ESTABLISHED

cat disable_game

#!/bin/sh

# DNS Rules

sed -e 's/^#//' -i /tmp/games-block.conf

sed -e 's/^#//' -i /tmp/yt-block.conf

restart_dns

# Force kids DNS to local
iptables -t nat -A PREROUTING -i br0 -s 192.168.1.128/28 -p udp --dport 53 -j DNAT --to 192.168.1.1

iptables -t nat -A PREROUTING -i br0 -s 192.168.1.128/28 -p tcp --dport 53 -j DNAT --to 192.168.1.1

# Block all ports over :500

iptables -I FORWARD 5 -p tcp --source 192.168.1.128/28 --dport 500:65535 -j DROP

cat allow_game

#!/bin/sh

# Remove DNS rules

sed 's/^\([^#]\)/#\1/g' -i /tmp/games-block.conf

sed 's/^\([^#]\)/#\1/g' -i /tmp/yt-block.conf

restart_dns

# Remove Force kids DNS to local

iptables -t nat -D PREROUTING -i br0 -s 192.168.1.128/28 -p udp --dport 53 -j DNAT --to 192.168.1.1

iptables -t nat -D PREROUTING -i br0 -s 192.168.1.128/28 -p tcp --dport 53 -j DNAT --to 192.168.1.1

# Unblock all ports over :500

iptables -D FORWARD -p tcp --source 192.168.1.128/28 --dport 500:65535 -j DROP

I do have an extra script that allow access to YouTube, without allowing games, this one is called only from a html page that I'll explain in a later post:

cat allow_yt

#!/bin/sh

sed 's/^\([^#]\)/#\1/g' -i /tmp/yt-block.conf

restart_dns

Those scripts are called by cron jobs that makes sure we don't have internet during the sleep hours and games & YouTube are permitted only during the weekend:

00 21 * * 0-4 root /jffs/add_fw

30 22 * * 5,6 root /jffs/add_fw

00 08 * * * root /jffs/del_fw

30 17 * * 5 root /jffs/allow_game

30 17 * * 0 root /jffs/disable_game

In order to block the DNS requests, the following Additional Dnsmasq Options needs to be added:

conf-file=/tmp/yt-block.conf

conf-file=/tmp/games-block.conf

The files /tmp/yt-block.conf and /tmp/games-block.conf are created by the startup script:

stopservice dnsmasq

echo "#address=/.roblox.com/192.168.1.1

#address=/.rbxcdn.com/192.168.1.1

#address=/.epicgames.com/192.168.1.1

#address=/.fortnitegame.com/192.168.1.1

#address=/.easyanticheat.com/192.168.1.1

#address=/.pixelgunserver.com/192.168.1.1

#address=/.applovin.com/192.168.1.1

#address=/.clashroyaleapp.com/192.168.1.1

#address=/.applifier.com/192.168.1.1

#address=/.chartboost.com/192.168.1.1

#address=/.fyber.com/192.168.1.1

#address=/.twitch.tv/192.168.1.1

#address=/.ttvnw.net/192.168.1.1

#address=/.leagueoflegends.com/192.168.1.1

#address=/.pvp.net/192.168.1.1

#address=/.riotgames.com/192.168.1.1

#address=/.garenanow.com/192.168.1.1

#address=/.ea.com/192.168.1.1

#address=/.respawn.com/192.168.1.1

#address=/.origin.com/192.168.1.1" > /tmp/games-block.conf

echo "#address=/.youtube.com/192.168.1.1

#address=/youtube.googleapis.com/192.168.1.1

#address=/youtubei.googleapis.com/192.168.1.1

#address=/.ytimg.com/192.168.1.1

#address=/ytimg.l.google.com/192.168.1.1

#address=/youtube.l.google.com/192.168.1.1

#address=/.googlevideo.com/192.168.1.1

#address=/.youtube-nocookie.com/192.168.1.1

#address=/.youtu.be/192.168.1.1" > /tmp/yt-block.conf

startservice dnsmasq

An "easy" way to run those scripts besides the scheduled cron jobs, is from the DD-WRT Administration -> Commands page: