Forum Discussion

Nimbostratus

Jul 19, 2026

Solved

Can BIG-IP perform DNAT before Virtual Server lookup?

Hi everyone I have a question about BIG-IP packet processing. As I understand it, the destination IP received by BIG-IP must match a configured Virtual Server. This can happen either because: - Th...

application delivery

Daniel_Wolf
Jul 21, 2026
In that case:
Watch this: BIG-IP Life of A Packet
And read this: K31591013: Packet flow | BIG-IP AFM operations guide

These two should give you really good insights on how packts flows through BIG-IP.

Daniel_Wolf

MVP

Jul 19, 2026

Hi Khun_Sophavatta,

The BIG-IP uses the destination address, source address, and service port to match incoming traffic to a virtual server.
But also the BIG-IP is a default deny device. This means, when no traffic processing objects are configured (for example a matching virtual server), the BIG-IP system does not process any network traffic.
For your question this means - the destination IP must match the Virtual Servers IP address, otherwise the BIG-IP won't do much with it.

Can you explain what you plan to do? Maybe we can suggest a solution.

Cheers
Daniel