Unreachable dns servers

[rezafathi]

Hi

I encountered a wired situation. When I enable web filter and dns filter in a policy, the dns servers on fortigate become unreachable or with high ping times and fortigate won't update at specified time. when i disable those security profiles the dns will have normal ping time. How can i solve this issue? I have tested with so many dns servers.

[AEK]

Hello

Run a nslookup from FGT's CLI and share how long it takes to get the answer.

[Bjay_Prakash_Ghising · Accepted solution]

Hi rezafathi

A possible issue could be of large payload used. Please find the attached article.

https://community.fortinet.com/t5/FortiGate/Technical-Tip-DNS-server-on-FortiGate-caused-FortiGate-D...

You may configure the appropriate setting considering the environment you have set.

Hope that helps, 

Kind Regards, 

Bijay Prakash Ghising