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Naftuli Kay
Asked: 2011-08-06 08:06:30 +0800 CST

How can I open a port on my EC2 instance?

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I'm working for a client here who has set up an EC2 instance for me to configure. I've installed the software asked for, now all I need to do is open up some ports. I'm currently SSH'd into the machine, it's running Ubuntu 10.04.

I've installed the ec2-ami-tools and the ec2-api-tools packages, and have tried running the following, as has been recommended elsewhere:

ec2-authorize -p 1024 default

Unfortunately, this just fails and leaves me with this nasty error message:

Required option '-K, --private-key KEY' missing (-h for usage).'

Evidently I need a key to do this, so I copied my PEM key which I received with the instance to the server and ran it again with the key:

ec2-authorize -p 1024 -K mykey.pem default

Now it's asking for a certificate:

Reqired option `-C, --cert CERT' missing (-h for usage).`

Ugh. I don't really have a certificate, so what exactly is it asking me for? I don't have access to the EC2 web interface, so how can I open a port from the Ubuntu server itself?

firewall amazon-ec2

3 Answers

  1. To use the ec2-api-tools you need to have a X.509 certificate: http://docs.amazonwebservices.com/AWSSecurityCredentials/1.0/AboutAWSCredentials.html#EC2Credentials

    To get your cerificate, you need to go to Account > Security Credentials > Access Credentials > X.509 Certificates. More details can be found at: http://docs.amazonwebservices.com/AWSSecurityCredentials/1.0/AboutAWSCredentials.html#X509Credentials

    You may be able to craft a request to the REST API using just your Access Keys and AuthorizeSecurityGroupIngress: http://docs.amazonwebservices.com/AWSEC2/latest/APIReference/ApiReference-query-AuthorizeSecurityGroupIngress.html

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  2. Easy way :

    go amazon ec2 console from your amazon account(web) and edit security group default

    More complex way:

    you have ask generate new certificate from person with access to web.

    sorry, i can't change security settings without have access(certificate), that have security reason ;) u need both key and cerificate.

    read this article

    http://cloud-computing.learningtree.com/2010/09/24/understanding-amazon-ec2-security-groups-and-firewalls/

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  3. Best Answer

    AWS issues X.509 certificates to authenticate these requests... You'll have to have the client go into AWS and generate one for you - there is no way to do what you are asking without proper authentication.

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