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

Forum Discussion

Richard_Gration's avatar
Richard_Gration
Icon for Nimbostratus rankNimbostratus
Oct 23, 2017

F5 Forwarding (IP) VS, VLAN and tunnels setting

Hi, When configuring a Forwarding (IP) virtual server there is an option to enable the VS only on certain VLANs. Does this apply to the source traffic, the destination traffic or both? Say I have...
big-ip
forwarding ip vs
LTM
security
Simon_Blakely's avatar
Simon_Blakely
Icon for Employee rankEmployee
Oct 24, 2017

The VLAN setting of a virtual defines the vlans that listen for incoming packets that establish a connection. Reply packets hit a vlan and are matched to an existing connection, defining the path through the LTM.

 

Please note, due to VLAN keying (which is a default setting), returning packets will only be matched to the connection table if they hit the egress VLAN. You can disable VLAN keying (with caveats).

 

Or will I just enable the inbound VS on VLAN 20 and only enable the outbound VS on VLAN 10?

 

This is correct.