I have amazon VPC set through wizard as \"public only network\", so all my instances are in public subnet.
Instances within VPC that have Elastic IP assigned connect
Security Groups -> Outbound
* ALL Traffic ALL ALL 0.0.0.0/0 Allow
Please allow Outbound, if you want to connect to external servers like google.com or even want to update- sudo apt-get update
You can allow the outbound using AWS front-end goto Security Groups -> Outbound
Make sure you select the right group for your AWS instance