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How to confirm a duplicate IP

 

Information

 

Summary:

Suddenly application stopped working through the LoadMaster.  Still able to ping the Virtual Service IP, but it doesn't seem to be responding to anything else.

Environment:

Product: LoadMaster

Version: Any

Platform: Any

Application: Any

Question/Problem Description:

The LoadMaster is not accepting any connections on the Virtual Service

Steps to Reproduce:  
Error Message: Connection Refused
Defect Number:  
Enhancement Number:  
Cause:

There was a duplicate IP within the network using the same IP address as the Virtual Service.

Even though the IP address of the service is reachable through ping tests, run a packet capture to verify if any requests or traffic is making it to the service.  To run a packet capture, go to:

  • System Configuration > Troubleshooting > TCP Dump > enter the IP of the Virtual Service in the Address field and the port it is configured on
  • This will show the front-end connection in which the user would connect to the Service.  If there is no traffic, nothing is reaching the LoadMaster and could be a duplicate IP
  • capture.png

A Virtual Service can also be de-activated/turned off within the configuration.  If a service is de-activated it will no longer be able to respond to ICMP requests.  If there are still successful pings after disabling a Virtual Service, this points directly to the issue being a duplicate IP.

  • To disable/de-activate a service, navigate to: Virtual Services > View Modify > Modify
  • modify.png
  • Once inside the Virtual Service configuration, un-check the box labeled "Activate or Deactivate Service."  This will turn off the Virtual Service if there is no check in the box.  Once checked, it will be turned back on, no reboot necessary.
  • de-activate.png

 

Resolution:

Changed the IP of the Service to an available IP that was not in use.

Workaround:  
Notes:  

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