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

Forum Discussion

GLM_191985's avatar
GLM_191985
Icon for Cirrus rankCirrus
Apr 08, 2019

dns works on 2 ports ?

dns works on 2 ports? port no is same tcp and udp 53 ? why do we need 2 ports. why we using 2 different protocols tcp and udp  
application delivery
LTM
stan_piron's avatar
stan_piron
Icon for Cumulonimbus rankCumulonimbus
Apr 08, 2019

Udp port is used to small size answers...

 

most of DNS servers respond to client to open a tcp connection If answer size is more than 512 bytes