Which one of the following is aport and protocol combination allowedby theAllow Defaultsetting for Port...

Port Lockdown controls which ports and protocols aSelf IPwill respond to.

TheAllow Defaultsetting permits only a predefined set of BIG-IP internal and required service ports.

The Allow Default listincludes:

TCP 443→ HTTPS (Management/TMUI access via Self-IP)

TCP 4353 → CMI (device sync)

TCP/UDP ports related to HA communication

Other essential internal F5 ports

Why TCP 443 is correct:

It is one of the officially allowed ports underAllow Default.

It enables HTTPS/TMUI access through a Self IP.

Why the other options are incorrect:

A. TCP 80 (HTTP)

Not allowed under Allow Default

HTTP via Self-IP is blocked unless placed under Allow Custom

B. UDP 8443

Not an F5 default service

Not part of the Allow Default ports