Firewall rules for DHCP?

Comodo Internet Security - CIS Firewall Help - CIS
#1

Hello Comodo community,

I had a question concerning DHCP. My modem that is provided by my ISP has a router inside of it and sometimes I lose connection for several seconds on my PC. When I look at my event viewer it tells me that my pc was unable to renew it’s address from the DHCP server.

What is the rule I need to add to my firewall to allow the DHCP to function properly?

Someone gave me this suggestion that’s not apart of the Comodo community so I figured I would ask if this would work?

They said to list this under Comodo’s Global Rules

Allow UDP In/Out from MAC Any to IP 255.255.255.255 Where Source Port Is Any And Destination Port Is Any.

Just some extra info.

I have svhost set to outbound only as I’ve seen mentioned numerous times on here.

#2

No don’t do that it’s far too general, you’ll open yourself up to a lot of problems that way.

DHCP uses ports 67 and 68 and your router’s IP address, which is often 192.168.1.1 (but check first). Your firewall rule should be:

Allow UDP In/Out from MAC Any to IP 192.168.1.1 Where Source Port is 67-68 and Destination Port is 67-68

#3

Regarding DHCP, I’ve allowed UDP Out to 255.255.255.255 where source port is any and dest port is 67 for svchost.

#4

I’ve changed the rule to this and I have no had any issues since then. Thank you for assisting me with a much more secure rule. I appreciate it a lot. Sorry it took so long to get back to you.

#5

Happy to have helped. :slight_smile: