topic Re: DNS traffic is not passing through firewall in General Topics

DNS traffic is not passing through firewall

Harish_Sankaran — Wed, 02 Sep 2020 07:44:46 GMT

Hi Folks,

We are trying to do nslook-up from out side through URL.We want see the traffic from the URL.

a)Any end user NSLOOKUP request coming from internet hitting website, It does not show logs in Firewall. Hence we are not able to detect connections as well as source IP address. We need detailed logs indicating NSLOOKUP request flow as well as Source IP details.

b)Is there any mode in Firewall for detailed log analysis. Currently limited logs are visible which may not be enough for any forensics if required.

Re: DNS traffic is not passing through firewall

HeikoAnkenbrand — Wed, 02 Sep 2020 19:15:36 GMT

Hi @Harish_Sankaran,

use the following cli commands
fw ctl zdebug drop | grep <source IP>
or
fw monitor -e "accept( host=<source IP>);"
to debug the traffic flow.

More to "fw monitor" could you found here:
R80.x - cheat sheet - fw monitor

Re: DNS traffic is not passing through firewall

Maarten_Sjouw — Wed, 02 Sep 2020 21:14:23 GMT

I don't really see what you are trying to identify here. When I use nslookup to resolve a URL like:

nslookup www.google.com

all that will happen is that my machine will contact the configured DNS server and ask the question at which IP I can reach www.google.com, nslookup will not send any packet to www.google.com itself.

Extended logging can be set by enabling accounting.