You can also use the internal IP address of the machine. i.e. with Windows insta...

		OmarIsmail on March 15, 2010 \| parent \| context \| favorite \| on: Tips to reduce Amazon ec2 costs You can also use the internal IP address of the machine. i.e. with Windows instances if you do an IP Config you'll see an address to the effect of 10.X.X.X. Instances in the same availability zone can communicate with one another using these IP addresses without leaving the network. This saves dramatically on costs and performance.

Sure, you can do that, but hard coding ephemeral IP addresses into your configuration is still problematic.