How to configure ASA for ASDM access

It this short post I will go through the steps of configuring ASDM access on an ASA device. I will use the ASAv 9.5.2 appliance just configured for GNS3 in previous post.

Copy the ASDM image to ASAv appliance

First, we need to copy a compatible ASDM image to ASAv internal storage. Therefor:

  1. Go to Cisco Download Software portal at Products > Security > Firewalls > Firewall Management > Adaptive Security Device Manager and download a compatible ASDM image for your ASA device. For download to success you will need a service contract associated with your cisco.com profile otherwise try a simple Internet search for a leaked image. Verify compatibility by consulting the Cisco ASA compatibility (link) article. For my ASAv version 9.5.2 an ASDM version 7.5.2.153 will compatible and sufficient.
  1. In GNS3, build a simple topology that will connect ASAv to some external network. To do that, connect one interface from ASAv to a cloud object configured to be linked to one of the host interface – for this purpose I usualy use a simple loopback adapter (for how to install such a one, read this technet article. reboot required). Because the ASA can’t connect directly to a cloud object a transit synthetic switch needs to be added. At this step, your topology should look like this:

How To configure ASA for ASDM access - topology view

Note0: Ethernet0 on ASA as presented by GNS3 correspond to Mangement0/0 intf seen from inside the device.

Note1: For a better look, changed the symbol/hostname used for cloud representation.

  1. On host computer start your favorite TFTP daemon (for this purpose I use tftpd32 from tftpd32.jounin.net. Configure the daemon directory and listening interface, additionally verify you host firewall to allow tftp protocol.

How To configure ASA for ASDM access - tftpd32 config

  1. Start the ASAv device and open the serial console. Configure interface IP settings, verify connectivity and copy the ASDM image to ASAv internal storage:

How To configure ASA for ASDM access - intf. configuration

A copy process should now begin. The progress seems to be less rapid than expected (in my case a top was the 60kbps) which could be because of unlicensed state of ASAv. In essence not a big problem, just wait for 3-5 minute for operation to complete. For confirmation do a dir command:

How To configure ASA for ASDM access - dir flash

Configure ASAv for ASDM access

Now it’s time to configure ASAv for ASDM access. Execute the following commands:

First two lines configure authentication, in this particular case against the local user database, second group of two commands enable HTTPS server and access from 192.168.49.0/24 network via mgmt interface (Management0/0) an the last command tell the firewall to use asdm-752-153.bin image for ASDM access.

Next, switch to your browser and try to open https for management interface https://192.168.49.100. If everything is ok, a security certificate error should appear in your browser, confirm the certificate exception to go forward. You should see a page like this:

How To configure ASA for ASDM access - ASDM welcome page

From this point you have two options: (a) via Java Plugins or (b) through ASDM Launcher. My preference is to use the ASDM Launcher. First install the ASDM Launcher – after click Install ASDM Launcher and successfully authentication a setup file will be made available for download, second start ASDM Launcher (icon on your desktop should be already present).

In ASDM Launcher authentication window, put the ASAv IP address and the authentication credentials.

How To configure ASA for ASDM access - ASDM launcher

Finally, after loading ASAv configuration, ASDM application should start:

How To configure ASA for ASDM access - ASDM view