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

Forum Discussion

ricky_paulus_gi's avatar
ricky_paulus_gi
Icon for Nimbostratus rankNimbostratus
Mar 08, 2019

Port should be opened to allow an AXFR/IXFR

Hi everyone,   is there anybody know " Which port should be opened to allow an AXFR/IXFR connection to be established to a DNS listener?"   It would be great if you have reference link for me t...
application delivery
BIG-IP DNS
Rico's avatar
Rico
Icon for Cirrus rankCirrus
Mar 11, 2019

TCP port 53 from here. Zone transfers need to ensure that all the data reached its destination so that a secondary DNS server can be sure it is serving out the right records. With UDP, there would be no way to know if the zone file transfer completed properly.