How to access/ping a server located on AWS?

Question

With what address should a server located on AWS be accessed?

I've created an AWS instance and installed a web server on it. However the server is not reachable via any of the:

1. ec2-174-129-24-92.compute-1.amazonaws.com
2. the IP address from instance's ifconfig
3. an elastic IP address I've created on the AWS dashboard and associated with the instance

Surprisingly, ssh with [email protected] works fine.

What might be the problem and how to bind an address to the instance?

Answer 1

In your security group open -1 to -1 on ICMP for range 0.0.0.0/0 and you'll be able to ping.

See my screenshot for a better view:

Image posted by @emostar below

Answer 2

Updated for 2014 - the current Amazon UI no longer uses numbers for ICMP types, so the existing answer doesn't work anymore.

In your security group:

• Click the inbound tab
• Create a custom ICMP rule
• Select echo request
• Use range 0.0.0.0/0 for everyone or lock it down to specific IPs
• Apply the changes

and you'll be able to ping.

Answer 3

As nowthatsamatt said, you want to allow ICMP from all addreses.

To do this on the command line you can run:

ec2-authorize <group> -P icmp -t -1:-1 -s 0.0.0.0/0

Or if you prefer the AWS Console, this is what it would look like (current as of 2012-09-19):

AWS Console Image

Answer 4

Ping doesn't work with EC2 because ping runs over the ICMP protocol which is blocked in a typical EC2 security group configuration.

Here's a very nifty way to work around this by using tcping (a ping alternative that works over a TCP port):

tcping ec2-174-129-24-92.compute-1.amazonaws.com

tcping ec2-174-129-24-92.compute-1.amazonaws.com 22

It runs on port 80 (the first example) but you can also specify a different port (the second example) to be used to test connectivity.