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Forum Discussion

jonathanw84's avatar
jonathanw84
Icon for Cirrus rankCirrus
May 21, 2021

Load Balance to FQDN Not Working

Hi All,   I have an environment that is set up on my F5 using a combination of Rewrite Profiles and iRules to achieve a reverse proxy setup. This works well.   I have a request to add an addi...
application delivery
BIG-IP
fqdn
iRules
rewrite
spalande's avatar
spalande
Icon for Nacreous rankNacreous
May 22, 2021

There could be many factors here. You can follow below troubleshooting steps.

- Check if firewall is open from F5 to the FQDN node port. Try with telnet comand from F5.

- Check routing is there on F5 and it's not using the mgmt route to reach. tmm route should be present on F5 to reach the FQDN.

- Check the health monitor if any custom http/https monitor configured. Try using tcp for troubleshooting.

- If F5 can connect on fqdn port. Check if node is up or down. disable ICMP monitoring at the node level.

- if FQDN node is in a non default route domain then there is no support for FQDN node currently. But there is a work around to it as per below

​

https://devcentral.f5.com/s/articles/FQDN-nodes-in-non-default-route-domains?page=1

​

  • jonathanw84's avatar
    jonathanw84
    Icon for Cirrus rankCirrus
    May 26, 2021

    Hi Sanjay,

     

    The firewall is definitely open. I can see the traffic going out to the FQDN node port. I've tried every monitor I can and they still revert back to marking it down. We are using the default route domain.

    • spalande's avatar
      spalande
      Icon for Nacreous rankNacreous
      May 27, 2021

      take tcpdump. if you are seeing packets are egressing out from your network and seeing RST coming from the other end. you would need to check with the FQDN hosting team.