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JustCooLpOOLe's avatar
JustCooLpOOLe
Icon for Cirrocumulus rankCirrocumulus
Nov 09, 2016

Heath Monitors, VLAN, Interface traffic

We are having issues with Health Monitors in iApps where they are marked down and then marked back up pretty quickly. The question came up as to which interface do these monitors go out. How does a pool determine which interface it goes out? At the Virtual Server level, we can assign a VLAN or just say "All VLANs and Tunnels" but at the Pool level (where we assign a monitor), how is the outgoing interface determined to perform a Monitor Health Check?

 

application delivery
LTM

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  • boneyard's avatar
    boneyard
    Icon for MVP rankMVP
    Nov 09, 2016

    it is determined by the outgoing interface, which is determined by the routing table. the IP of the poolmember will be checked against the routing table and based on that the egress interface will be selected.

     

    at the virtual server you don't configure the egress interface with selecting VLANs, you select the ingress interface.

     

  • David__Pasch's avatar
    David__Pasch
    Icon for Altostratus rankAltostratus
    Nov 09, 2016

    boneyard nailed the answer: The routing table

     

    An easy trick to figure this out during a troubleshoot is to use the tracepath command to the node IP from the big-ip device. The first hop will be your egress interface.

     

    From bigip:

     

    tracepath 1.1.1.1

     

    Good Luck!