Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

T0nyP's avatar
T0nyP
Icon for Cirrus rankCirrus
Apr 01, 2022

F5 DNS what specific TCP/UDP port need to open?

Hi F5 Community, We are restricting thru Port Lockdown our F5 DNS system which is facing Internet. Does UDP/53 and TCP/4353 already enough? Or we still need to open both TCP/UDP 53 and TCP/UDP 435...
application delivery
DNS
T-Trust's avatar
T-Trust
Icon for Cirrostratus rankCirrostratus
Apr 02, 2022

Hi

So i think if you would like to enable about security DNS or zone transfer, You have to open TCP 53 and TCP 4353 for protocol IQUERY

 

Thanks you