Thursday, December 31, 2015

Awesome Star Wars ASCII Animation

With the recent release of Star Wars: The Force Awakens, I figured that it's an opportune time to share this.

When you have a couple minutes to kill, telnet to for some awesome Star Wars ASCII animation.

Tuesday, December 29, 2015

Calculating MD5 Checksum in Windows

Thanks to PowerShell, you can calculate the MD5 checksum of a file in Windows without having to download any additional utilities.

For these examples, I'm going to be using a file called asa924-k8.bin with an MD5 checksum of 4558b27d0dd7ba1751e43b0ba33593a3.

The example file's download page showing its MD5 checksum

To calculate the MD5 checksum of a file, open a PowerShell window and run this command.

Get-FileHash -Algorithm MD5 'C:\Path To\YourFile.exe'

If you want to take it a step farther, you can compare the file's calculated MD5 checksum against the original MD5 checksum that you got from the download page (or wherever) with this command.
Hint: You can paste into PowerShell by right-clicking.

(Get-FileHash -Algorithm MD5 'C:\Path To\YourFile.exe').hash | Compare-Object <Original MD5 Checksum> -IncludeEqual

Output when the checksums are equal

Output when the checksums are not equal

Thursday, December 24, 2015

Permitting PPTP VPN Connections through a Cisco ASA

I had a client who uses a PPTP-based VPN client to connect to one of his customer's networks. He was having trouble getting his VPN client to connect after a new ASA was installed on their network. Fortunately, all I had to do was enable PPTP inspection.

To enable PPTP inspection, SSH or console into your ASA and run the following commands in global config mode.

ASA(config)# policy-map global_policy
ASA(config-pmap)# class inspection_default
ASA(config-pmap-c)# inspect pptp