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The server works fine via the Amazon assigned DNS entry, but I cannot reach it (using a browser) via the Elastic IP address Amazon assigned the box. Ping does not work either. I am trying to confirm it is reachable before I add the IP address to my own DNS entries.

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migrated from Feb 3 '12 at 16:51

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Are you sure you're using your elastic IP and not your private, could-local IP? – Piotr Justyna Feb 3 '12 at 16:34
@Robert - Hi, well the aws.*** address will not lookup via ping, (but works in the browser) so I am actually at a loss on how to find out. I tried ping and I tried a few internet sites that do a lookup. – Guido Anselmi Feb 3 '12 at 16:42
@Piotr - Yep. It's the "Elastic IP Address" not the Private IP Address. It also is used by Amazon in the header for the status tabs. – Guido Anselmi Feb 3 '12 at 16:43
Guido, does it have a public DNS and instance ID assigned? – Piotr Justyna Feb 3 '12 at 16:46
@Piotr - Yes. And the public DNS is reachable via a browser. Currently I am working behind a firewall, not sure if that will affect.....just attempted to ping a known site ( and that failed. Tethering my phone... – Guido Anselmi Feb 3 '12 at 17:12
up vote 17 down vote accepted

Things to check:

  • Your elastic IP associated with your instance?
  • Your security group of instance permits incoming connections?
  • Your instance firewall permits incoming connections?
  • Your application listens?
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As others mentioned, the security group for your EC2 instance may not allow the HTTP port.

First,find the Security Group your instance is using.

enter image description here

Then, under Network & Security, go to the Security Groups section. Select your instance's security group and add an Inbound Custom TCP rule for Port range 80.

Security Groups in EC2

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The 1st adequate answer - thx a lot. – zeusakm Jun 11 '15 at 13:10
I`d rather accepted this answer, because AWS EC2 really creates instance without opened port 80 for TCP connections by default. – zeusakm Jun 11 '15 at 13:13
Much better answer than Stone's answer. This (James') answer should be accepted as correct answer because it is an actual answer. Stone's respond is too generic ie. Things to check! – kannas Apr 7 at 18:30

Just adding this reply as it might help other EC2 Newbies. If the Public DNS for your EC2 instance is: Public DNS: you can access the instance using the numeric portion of the DNS Address. In the above case

Obviously you will need to have the relevant TCP Port open in the security group/profile associated with your instance as mentioned above.

The private IP (e.g. is not accessible from outside the AWS network and is only useful when you have a cluster of EC2 nodes and want faster communication between them.

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Also make sure Route table of VPC is set to enable IP address outside the VPC ( to flow from the subnet to the Internet gateway.

Navigate to VPC > Route Tables ; Route tab. Check Destination is 'mapped' to Target Internet Gateway Id (apart from local).

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Couple questions: what port are you trying to access? Do you have that port open on the security groups? Do you have an application listening on that port?

If I had to guess your security groups are not setup right. Make sure to open them to the correct ip addresses or to the world ( if you are going access that port from multiple IPs.

If all that is not it, then dissociate and reallocate the IP to the instance.

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@Chan-da-man- Yes ports are open and there is an app listening. Exact same URL except domain name swapped with IP. – Guido Anselmi Feb 3 '12 at 18:04
When you ping the full amazon cname does it come back with the elastic ip? – chantheman Feb 4 '12 at 17:50

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