Block all traffic to LAN except certain URL

[abidkhan]

Hi, i have following this thread to setup the rules in the opnsense but i am little confused,

https://forum.opnsense.org/index.php?topic=6017.0

but i am little confused about following instructions,

(make a rule to allow DNS traffic to your DNS Server
make a rule to allow HTTP traffic to alias ALLOWED_HOSTS)

can someone give me sample config about this so i can replicate it on my LAN firewall Tab, thanks.

[abidkhan]

anyone?