Forum Discussion

David_Tumlin's avatar
David_Tumlin
Icon for Nimbostratus rankNimbostratus
Aug 06, 2018

GTM/DNS Datacenter question

I have a question regarding the functioning of the F5 DNS product.

 

The environment: Multiple datacenters, each with a GTM and multiple LTMs GTMs are in a single sync group

 

A firewall misconfiguration blocks iQuery access from the GTM and LTMs within a datacenter, but the LTMs still have iQuery communication with all other datacenters and their GTMs. All (GTM) pool members on the LTMs in the affected datacenter are marked as down, despite continuing to communicate with most of the GTMS.

 

Is this expected behavior? Does the GTM in the same Datacenter take priority over all others? I could find no documentation that explained this.

 

application delivery
BIG-IP DNS
  • Andy_McGrath's avatar
    Andy_McGrath
    Icon for Cumulonimbus rankCumulonimbus
    Aug 06, 2018

    Yes this is expected behavior. Each GTM/DNS in a sync group needs to be able to communicate via iQuery with all other F5 devices configured, so all other F5 DNS/GTM devices and all LTM devices.

     

    When using iQuery (bigip) to monitor other F5 devives results are not shared from one F5 DNS/GTM to others within the group as iQuery basically broadcast information so if all connections are working correctly no need to share data, also iQuery can contain a lot of information so you don't want to duplicate network traffic if not needed.

     

    I know is because i asked the same thing a while ago on DevCentral, see the following link: GTM Sync Group, sharing state information