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

Forum Discussion

abdel_387674's avatar
abdel_387674
Icon for Nimbostratus rankNimbostratus
Apr 03, 2019

From Server, Contact the Web Site hosted on this same Server by the public IP of VS

Hello,   Sorry for my english.   I m trying to contact the web site hosted on ServerA that is present in the private network, by its own VS (Public IP) .   Example: The Web Site hosted on Se...
big-ip
cloud
Kai_Wilke's avatar
Kai_Wilke
Icon for MVP rankMVP
Apr 03, 2019

Hi abdel,

this is most likely a asymetric routing issue, which is by design if you don't have any Source NATs in place.

Request: 

ServerA -> (SRC_IP=A -> DST_IP=X) -> F5 -> (SRC_IP=A -> DST_IP=A) -> ServerA 

Response: 

ServerA -> (SRC_IP=A -> DST_IP=A) -> ServerA

Since ServerA has never created a connection to itself, the connection will simply break.

The solution would be to enable SNAT globally on the Virtual Server or via an iRule if the SRC_IP is matching certain subnets (those which would otherwise experience asymetric routing issues).

Cheers, Kai