Connecting to Linux/UNIX Instances from Windows Using PuTTY

To connect to your Linux/UNIX instance from a Windows computer, use

an SSH client. The following instructions explain how to use PuTTY,

a free SSH client for Windows computers.

Prerequisites

Enable SSH traffic—Open the instance's

SSH port

Before you try to connect, ensure that your Amazon EC2 instance

accepts incoming SSH traffic (usually on port 22). For more

information, see

Instance ID—Get the ID of your Amazon

EC2 instance

Retrieve the Instance ID of the Amazon EC2 instance you want to

access. The Instance ID for all your instances are available in the

AWS Management Console or through the CLI

command

Instance's public DNS—Get the public

DNS of your Amazon EC2 instance

Retrieve the public DNS of the Amazon EC2 instance you want to

access. You can find the public DNS for your instance using the AWS

Management Console or by calling the CLI

command ec2-describe-instances.

The format of an instance's public DNS is

ec2-w-x-y-z-compute-1.amazonaws.com where w, x, y, and z each

represents a number between 0 and 255 inclusive.

Private key—Get the path to your

private key

You'll need the fully qualified path of the private key file

associated with your instance. For more information on key pairs,

see

Getting

PuTTY

To download and

install PuTTY

Other tools in the PuTTY suite are

PuTTYgen, a key generation program, and pscp, a secure copy command

line tool. The different PuTTY tools are separate applications. You

can install them separately or install the entire suite with a

simple Windows installer. The following instructions assume you've

installed the entire suite and can access all the components from

the Windows Start menu.

Converting

Your Private Key

PuTTY does not natively support the

private key format generated by Amazon EC2. Fortunately, PuTTY has

a tool called PuTTYgen, which can convert keys to the required

PuTTY format.

To convert your

private key

Start PuTTYgen (for example, from

the Start menu,

click All Programs > PuTTY >

PuTTYgen).

Click Load and browse to the

location of the private key file that you want to convert

(e.g., GSG_Keypair.pem).

By default, PuTTYgen displays only files with

extension .ppk; you'll

need to change that to display files of all types in order to see

your .pem key

file. The private key file must end with a newline character or

PuTTYgen cannot load it correctly.

Select

your .pem key

file and click Open.

PuTTYgen displays the following

message.

When you click OK, PuTTYgen displays

a dialog box with information about the key you loaded, such as the

public key and the fingerprint. The keys that Amazon EC2 generates

are 1024-bit SSH-2 RSA keys.

Click Save private

key to save the key in PuTTY's format.

PuTTYgen asks if you want to save the key without a passphrase.

Click Yes.

Note

A passphrase

on a private key is an extra layer of protection, so even if your

private key is discovered, it will not be usable without the

passphrase. The downside to using a passphrase is that it makes

automation harder because human intervention is needed to log on to

an instance, or copy files to an instance. For this exercise, we're

not using a passphrase.

Use the same name for the key that

you used for the key pair (for example, GSG_Keypair). PuTTY

automatically adds the .ppk file

extension.

Your private key is now in the

correct format for use with PuTTY. You can now connect to your

instance using PuTTY's SSH client.

Connecting

Using PuTTY SSH

You'll connect by starting a PuTTY

SSH session.

To use SSH to

connect

If you've launched a public AMI that

isn't one that you created yourself, run

the ec2-get-console-output command

on your local system (not on the instance), and locate

the SSH HOST KEY

FINGERPRINTS section. For more information,

see ec2-get-console-output in

the Amazon Elastic Compute

Cloud Command Line Reference.

C:\>ec2-get-console-output instance_id

...

ec2: -----BEGIN SSH HOST KEY FINGERPRINTS-----

ec2: 2048 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

/etc/ssh/ssh_host_key.pub

ec2: 2048 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

/etc/ssh/ssh_host_rsa_key.pub

ec2: 1024 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

/etc/ssh/ssh_host_dsa_key.pub

ec2: -----END SSH HOST KEY FINGERPRINTS-----

...

Note the fingerprints so that you

can compare them to the fingerprints of the instance.

Start PuTTY (from

the Start menu,

click All Programs > PuTTY >

PuTTY).

A dialog box opens with a Category menu on

the left side. On the right side, the basic options for your PuTTY

session are displayed.

In the Host

Name field, enter the public DNS name of

your instance (available through the AWS Management Console or

the ec2-describe-instancescommand).

You can optionally prefix the DNS name

with [email protected] to

automatically log in with superuser privileges when the session

opens.

In the Category menu,

under Connection,

click SSH, and

then Auth.

The options controlling SSH authentication are displayed.

Click Browse and navigate to

the PuTTY private key file you generated in the preceding

section.

Click Open.

An SSH session window opens and PuTTY displays a security alert

asking if you trust the host you're connecting to.

Important

If you've

launched a public AMI, verify that the fingerprint in the security

alert matches the fingerprint from the output of

the ec2-get-console-output command.

If it doesn't, someone might be attempting a "man-in-the-middle"

attack.

Click Yes.

In the SSH session window, log in as

root (or ec2-user) if you didn't as part of starting the SSH

session.

Note

Some AMIs let

you log in as root, but some require you to log in with the

username ec2-user. For log in information for your chosen AMI,

contact your AMI provider directly or go

to Amazon Machine

Images(AMIs) page, then locate and click your

AMI on the list.

Note

If you

specified a passphrase when you converted your private key to

PuTTY's format, you must provide that passphrase when you log in to

the instance.

Transferring Files with PSCP

The PuTTY Secure Copy Client (PSCP)

is a command-line tool that lets you transfer files between your

Windows computer and your Linux/UNIX instance.

To use PSCP, you'll need the private

key you generated in Converting Your Private Key. You'll

also need the public IP address of your Linux/UNIX instance.

The following example transfers the

file sample_file.txt from

a Windows computer to the /usr/local directory

on a Linux/UNIX instance:

C:\>pscp -i C:\GSG_Keypair.ppk C:\sample_file.txt [email protected]:/usr/local/sample_file.txt

If you prefer a graphical user

interface (GUI), you can use an open source GUI tool named WinSCP.

For more information, go to the