topic Re: How to clear the DNS Cache in Checkpoint Firewall. in Firewall and Security Management

How to clear the DNS Cache in Checkpoint Firewall.

Rabindra_Khadka — Mon, 01 Feb 2021 05:22:31 GMT

Do you have an idea regarding "How to clear the DNS Cache in Checkpoint Firewall".

We remove the DNS server in checkpoint Gateway but it still sends the DNS query to the DNS server.

Thank You

Re: How to clear the DNS Cache in Checkpoint Firewall.

PhoneBoy — Mon, 01 Feb 2021 07:11:41 GMT

You mean you removed the configured DNS server from Gaia OS so none is configured?
Very much not a recommended configuration as MANY services require DNS and will not function properly without it.

In any case, this may be cached elsewhere in the Security Gateway and cprestart (outage inducing) may be required to clear it.

Re: How to clear the DNS Cache in Checkpoint Firewall.

Rabindra_Khadka — Mon, 01 Feb 2021 14:03:52 GMT

I have configured a proxy server for updates and DNS resolving, so I don't need DNS server configuration in my checkpoint firewall and I have removed it.

However, the firewall is still trying to connect to the DNS server.

I checked the proxy configuration and it is working fine. My firewall is reaching the internet via a proxy server.

Does it really require rebooting the firewall?

Re: How to clear the DNS Cache in Checkpoint Firewall.

Vladimir — Mon, 01 Feb 2021 14:41:07 GMT

You should be using your internal DNS server for Check Point gateways.

If your internal DNS server forwarding the DNS requests to a DNS proxy, you will not be connecting from the gateway to the public DNS and would fill the requirements without breaking functionality.

Re: How to clear the DNS Cache in Checkpoint Firewall.

PhoneBoy — Mon, 01 Feb 2021 22:40:20 GMT

There are still other reasons DNS are needed on the gateway, so not having this configured is NOT recommended.
A cprestart is NOT a reboot, but it does restart all Security Gateway services (and causes an outage).