Cisco ASDM or Adaptive Security Device Manager is a Java based GUI for Cisco ASA devices.
To enable ASDM access on a device you must first ensure an ASDM image is loaded to the devices flash. To check if you have an ASDM image in flash enter the following command at your routers exec prompt: “show flash“, you are looking for a file named asdm-###.bin where the #’s are the ASDM version. If you don’t have the file you’ll need to download an appropriate version of ASDM this will require a valid CCO ID or some Google foo.
Once your image is in flash simply enter the following config via the CLI exchanging the IP addresses for your own. This config also assumes you want to use a local authentication, if this isn’t the case then you’ll need to modify the AAA config to meet your requirements:
aaa authentication http console LOCAL username <YOUR USER> password <YOUR PASSWORD> interface <Inside Int> nameif inside ip address 192.168.1.1 255.255.255.0 no shutdown http server enable http 192.168.1.0 255.255.255.0 inside asdm image <FLASH LOCATION>:/asdm-<VER>.bin