DNS Request to VS?

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1

Hello,

we found on our Firewall lots of DNS-Requests from the floating IP to some VS (with ASM-Policy).

Now we want the Firewall to only allow DNS-Requests to the known DNS-Servers.

Question: is this normal behaviour? The BIGIP has DNS-Resolver configured.

Where can I check the Config-Utility?

Thanks for any hint.

Karl

2

@kgaigl

Hello here is some information that I was able find (Formatting generated by AI)

https://my.f5.com/manage/s/article/K15430

https://my.f5.com/manage/s/article/K21272

https://my.f5.com/manage/s/article/K13221

You can check and modify the DNS Resolver settings in the BIG-IP UI (Configuration Utility) by following these steps:

  1. Log in to the Config-Utility (GUI):
    • Open a browser and navigate to your BIG-IP management IP or hostname (e.g., https://<management-ip>).
    • Log in with your management credentials.
  2. Navigate to the DNS Resolver Settings:
    • Go to System > Configuration > Device > DNS.
    • Check the settings under DNS Resolver or System DNS configuration.
    • Verify the listed DNS servers are the expected ones.
  3. Check Virtual Server (VS) and ASM Policies:
    • Navigate to Local Traffic > Virtual Servers to review the virtual server bound to the floating IP.
    • Locate the associated DNS Resolver profile, if any, and associated policies.
    • For ASM: Under Security > Application Security > Policy Building or Policies, ensure policies are configured correctly and not triggering unintended DNS lookups.

You can check and modify the DNS Resolver settings in the BIG-IP UI (Configuration Utility) by following these steps:

  1. Log in to the Config-Utility (GUI):
    • Open a browser and navigate to your BIG-IP management IP or hostname (e.g., https://<management-ip>).
    • Log in with your management credentials.
  2. Navigate to the DNS Resolver Settings:
    • Go to System > Configuration > Device > DNS.
    • Check the settings under DNS Resolver or System DNS configuration.
    • Verify the listed DNS servers are the expected ones.
  3. Check Virtual Server (VS) and ASM Policies:
    • Navigate to Local Traffic > Virtual Servers to review the virtual server bound to the floating IP.
    • Locate the associated DNS Resolver profile, if any, and associated policies.
    • For ASM: Under Security > Application Security > Policy Building or Policies, ensure policies are configured correctly and not triggering unintended DNS lookups