identification rule for cmdb_ci_linux_server cant find match

[vintotz]

I have an issue with discovery for linux servers every time the discovery runs, it create duplicate.

I tried checking the Identification simulation and it says "NO_MATCH", 

what could be the possible reason on this?

[chrisberg]

Looks like you have customized the IRE, that is looking to have the Name Serial Number populated, and if either one is empty, by default the Allow Null is not selected, so you have prolly one of those 2 NULL.
Below is OOB IRE which is inherited from hardware.   you will need to 1. debug the Linux discovery on the device, the see what is builds, or get the LOGS that show the IRE packet that was built.