DNS Server

ihernandez · January 13, 2010, 3:06pm

Hello wise people!, I have a question for you:

I would like to know if its possible to use a routerboard with router os to substitute temporarily a DNS server. If the answer is yes, how would I do it and how would I protect it from being used outside my network.

Chupaka · January 13, 2010, 3:24pm

what functionality do you need from DNS?

ihernandez · January 13, 2010, 4:08pm

Only basic functions, name resolution and DNS caching

fewi · January 13, 2010, 4:12pm

Yes. http://wiki.mikrotik.com/wiki/DNS

To block outside access, simply add a firewall rule like this:

/ip firewall filter add chain=input in-interface=<your WAN interface> protocol=udp dst-port=53 action=drop

To block access to udp/53 via the WAN interface. Make sure you accept established/related connections above that so that the router does get back DNS replies it asked for.

ihernandez · January 13, 2010, 6:47pm

fewi:

Yes. http://wiki.mikrotik.com/wiki/DNS

To block outside access, simply add a firewall rule like this:
/ip firewall filter add chain=input in-interface=<your WAN interface> protocol=udp dst-port=53 action=drop
To block access to udp/53 via the WAN interface. Make sure you accept established/related connections above that so that the router does get back DNS replies it asked for.

Thank you fewi, once again you help me. I will try it and let you know.