Forum Discussion

adam_gibs's avatar
adam_gibs
Icon for Nimbostratus rankNimbostratus
Feb 08, 2024

One Arm Mode

Dears

if an f5 is connected with 3 different  interfaces with different IP subnet  ( 172.24.1.0, 172.24.2.0, 172.24.3.0 ) to the L3 switch having a L3 Interfaces 172.24.1.1, 172.24.2.1, 172.24.3.1) still the f5 will be called as a one arm mode setup. please correct me if i m wrong.  Any incoming VIP traffic if it hits the VIP i will route the traffic  from the same interface back to the switch towards the pool servers.

Is there any glitch in the design.? expert advise please

application delivery
  • whisperer's avatar
    whisperer
    Icon for MVP rankMVP
    Feb 08, 2024

    Are you using a separate address subnet for the hosted VIPs? Are you planning to use SNAT? Will all pool members reside within the 3 subnets you have created and referenced above?

    The following is a great resource I would read carefully and watch the video: https://my.f5.com/manage/s/article/K54312549.

  • Paulius's avatar
    Paulius
    Icon for MVP rankMVP
    Feb 08, 2024

    adam_gibs The F5 is considered to be in one-arm mode if it is not the gateway for devices in a subnet in which it resides for routed traffic.

  • adam_gibs's avatar
    adam_gibs
    Icon for Nimbostratus rankNimbostratus
    Feb 08, 2024

    Dear Experts

    I will use the different subnet for the hosted VIP, and also i will do the SNAT with self IP, the pool members will be having a different IP subnet that will be of inside DC subnet, as far as the f5 know the route it should not be a problem

     

    example 1

    Self IP: 172.24.1.2

    VIP: 172.24.1.3

    192.168.10.0 route will be pointed to L3 Switch IP address 172.24.1.1

    pool members in data center subnet: 192.168.10.2,192.168.10.3,192.168.10.4.

    SNAT with Self IP: 172.24.1.2

     

    Example 2:

    Self IP: 172.24.2.2

    VIP: 172.24.2.3

    192.168.11.0 route will be pointed to L3 Switch IP address 172.24.2.1

    pool members in data center subnet: 192.168.11.2,192.168.11.3,192.168.11.4.

     

    Thanks