Came across a weird error on Cisco ASA today. I was working on ASA hardware upgrade, loaded backup configuration file from old unit no problems and tried to add IP address to Management interface when got this error:
Cisco ASA: 9.6.2
(config-if)# ip add 10.10.10.10 255.255.255.0
ERROR: Address is in use by routing instance of different network type
Same issue on ASDM.
First, I thought it was a bug, got it upgraded but same error. Surprisingly nothing came up in online search so after several hours of trial and error the fix was found to be related to removing dynamic routing configuration. In this case EIGRP.
Prior configuration looked as follows.
router eigrp 100
eigrp router-id 10.10.1.1
network 10.10.0.0 255.255.0.0
Once I’ve issued command below I was able to configured IP address on Management interface.
no router eigrp 100
So my assumption is routing statement somehow was preventing addition of another ip subnet in 10.10.x.x range.
After new interface was configured I’ve reapplied EIGRP and all worked as expected.