ASA serial numbers not discovered on some ASAs. All other fields are discovered (ie SW version)

[mellwang]

We are discovering ASA devices but only two of the 20 collected have serial numbers.  The other are blank.   Every other filed is collected (i.e. SW version) only the serial number is missing.  

[Chris Camplejohn]

Can you share the SW Version running on the 2 that work and the 18 that don't have it?

[mellwang]

The ASA that do not have a serial number are 8.4(1), 9.1(1), and 9.1(2).

The ASA's that do have serial numbers are both 9.1(1)

[Chris Camplejohn]

There have been several changes with how serial numbers are reported by the ASA itself.  One issue is whether the ASA is reporting the PCB serial number or the actual chassis serial number.  You can see if there was a collected serial number by looking at the all equipment page and showing the collected serial number field (hidden by default).  

The other limitation will be if the firewalls are actually user contexts versus the admin context.  Only the admin context will reliably provide the hardware information.