This is the third part of my series on Amazon EC2 security groups. In part 1, I described how security groups are possibly the most underappreciated feature in EC2. In part 2, I described a UDP hole punching technique, which led to some interesting conclusions. On several occasions, when troubleshooting...

Disclaimer 1: Despite its possibly ominous name, this is NOT a network vulnerability or an attack that could lead to unauthorized access. UDP hole punching requires cooperation between two hosts, and hence can't be easily used as an attack by itself (in other words, in order to run it, you...

Having been developing software to run on Amazon EC2 for over a year now, I find security groups to be among its least understood and appreciated features. Basic Usage In short, EC2 security group (SG) is a set of ACCEPT firewall rules for incoming packets that can apply to TCP,...