EC2 instances not responding to internal ping

I did a script that launch several amazon instances with the same security group which is the default one, with ICMP and all the TCP/UDP connection allowed... so no firewall problem. I am running an ubuntu 11.4 64 bits ami working fine.

Usually in the bunch of machine I launch some do not respond to any ping or telnet connection. They can ping other machines but cannot be pinged. The other machines can ping each other in two directions without any problem, but usually one or two just don't respond to any ping. There is no difference in the way I launch them, so I don't understand w开发者_JS百科here this bug comes from...

How to avoid this problem and recover from it without restarting the EC2 instance?

Thanks a lot tender developpers :D.

try this

1. Log into AWS account.
2. Click on Security Groups. Choose the required security group.
3. Click on the Inbound tab.

Create a new rule:

Custom ICMP rule
Type: Echo request
Source: 0.0.0.0/0
0.0.0.0 will allow everyone to ping your server. You can specify your own addresses if you want.

Assuming all the instances you launch have the same security group and same ami, you need to contact amazon about this.

https://forums.aws.amazon.com/thread.jspa?threadID=22640