Introduction
Installing the management software ASDM for Cisco ASA firewalls on a modern computer is very often a big hassle and it rarely works as intended on the first try in many cases. Cisco still supports the (now) older ASA operating system, which is still running strong even on Cisco’s latest firewall hardware. For some features, like remote-access VPN, I actually prefer working with the ASA operating system rather than Cisco’s newer Firepower operating system, or FTD for short.
The Problem
Getting ASDM to install can be very frustrating, especially if you are in a hurry to troubleshoot a network that is new to you, and you don’t have ASDM currently installed on your computer.
Installing ASDM is usually done by downloading the software from the firewall itself, by visiting the web page https://<FW-MGMT-IP>/admin. For example, the management IP address of my ASA firewall is 10.1.1.254 so the URL to visit to access ASDM is usually https://10.1.1.254/admin
This will redirect you to a page similar to the one below.
If neither of the installation alternatives does NOT work for you no matter what you try, there is a way to directly fetch the Java component of the ASDM-application and run it directly on your computer, without installing the software. Even on computers that have refused to install ASDM, this method has worked for me very often, but not in 100% of the cases.
The Workaround
Try connecting to this URL instead of the regular “admin” URL:
https://<FW-MGMT-IP>/admin/public/asdm.jnlp
In my case, I would access the URL https://10.1.1.254/admin/public/asdm.jnlp
You should be asked to open or download a Java file. Select to open the file and click on OK.
Instead of the regular ASDM-installer being launched, you will, for a second, see that Java itself is launching directly, like in the image below.
Depending on your computer and its settings, you might be asked to confirm that you really want to launch the Java application. Click on Run to continue.
After a few seconds, Java will have finished launching the application and you should be greeted with the regular ASDM login screen. After entering valid credentials, ASDM will launch.
And you are done!