I've configured the management interface on our ASA 5550. The address is 192.168.254.5 and it's next hop is .1 (vlan 254 on 3750).
I can ping the management interface fine from my laptop (10.128.100.75), but I can't telnet to the device on the management interface and it gives the following error:
%ASA-6-110003: Routing failed to locate next hop for TCP from management:192.168.254.5/23 to management:John-Blakley/2223
I can't add the route as "route management 10.128.100.0 255.255.255.0 192.168.254.1" because it says that it overlaps with an existing route. The 10.128.100.0 subnet will be exiting out of the inside interface.
What have I missed?
You could try adding a specific route for your laptop out of the management interface but then that would break your Internet access from your laptop.
Problem is telnet is stateful TCP - so the packet enters the ASA on the management interface but then the ASA cannot find a route back to your laptop via that same interface so it drops it.