Block All and Allow 50 IPs

ukhan20 You should be able to create an address list that encompasses the 5,000 IPs and use that in your firewall rule that allows those IPs to reach the virtual server, which would be the destination with the appropriate ports, and then if you aren't blocking everything by default you would need to add a rule to block everything else attempting to reach that virtual server IP. The following should be how to create the address list.

https://techdocs.f5.com/kb/en-us/products/big-ip-afm/manuals/product/big-ip-network-firewall-policies-and-implementations-14-1-0/03.html

ukhan20 - if Paulius' answer solved your problem please consider choosing 'Mark As Solution' - it helps our community when they have similar questions in the future.

Cheers,

-Lief