This post aims to show how you can connect to a remote VM server using Telnet/SSH Secure shell with a free program called Putty on Windows. This not an advanced guide, I hope you find it useful.

You will learn how to connect (via Windows) to a remote computer (Linux) over the Telnet protocol using SSH (Secure Shell). Once you login you can remotely edit web pages, learn to code, install programs or do just about anything.

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Common Terms (Glossary)

  • Putty: Putty is a free program that allows you to connect to a server via Telnet. Putty can be downloaded from here.
  • Port: A port is a number given to a virtual lane on the internet (a port is similar to a frequency in radio waves but all ports share the same transport layer frequency on the internet). Older unencrypted webpages work on Port (lane 80), older mail worked on Port 25, encrypted web pages work on Port 443. Telnet (that SSH Secure Shell uses) used Port 22. Read about port numbers here.
  • SSH: SSH is a standard that allows you to securely connect to a server over the telnet protocol. Read more here.
  • Shell: Shell or Unix Shell is the name given to the interactive command line interface to Linux. Read more about the shell here.
  • Telnet: Telnet is a standard on the TCP/IP protocol that allows two-way communication between computers (all issent as characters and not graphics). Read more on telnet here and read about the TCP protocols here and here.
  • VM: VM stands for Virtual Machine and is a name given to a server you can buy (but it is owned by someone else). Read more here.

Read about other common glossary terms used on the here:
https://en.wikipedia.org/wiki/Glossary_of_Internet-related_terms

Background

If you want a webpage on the internet (or just a server to learn how to program) it’s easier to rent a VM for a few dollars a month and manage it yourself (with Telnet/SSH Secure Shell) than it is to buy a $5,000 server, place it in a data centre and pay for electricity and drive in every few days and update it. Remote management of VM servers via SSH/Secure Shell is the way for small to medium solutions.

  • A simple web hosting site may cost < $5 a month but is very limited.
  • A self-managed VM costs about $5 a month
  • A website service like Wix, Squarespace, Shopify or WordPress will cost about $30~99 a month.
  • A self-owned server will cost hundreds to thousands upfront.

There are pros and cons to all solutions above (e.g cost, security, scalability, performance, risk) but these are outside this post’s topic. I have deployed VMs on provides like AWS, Digital Ocean, Vultr and UpCloud for years. If you need to buy a VM you can use this link and get $25 free credit.

I used to use the OSX Operating System on Apple computers. I was used to using the VSSH software program to connect to servers deployed on UpCloud (using this method). With the demise of my old Apple Mac book (due to heat) I have moved back to using Windows (I am never using Apple hardware again until they solve the heat issues).

Also, I prefer to use Linux servers in the cloud (over say Windows) because I believe they are cheaper, faster and more secure.

Enough talking lets configure a connection.

Public and Private Keys?

Whenever you want to connect to a remote server via Telnet/SSH Secure Shell you will need a public and private key to encrypt communications between you and the remote server.

The public key is configured on your server (on Linux you add the public key to this file ~/.ssh/authorized_keys).

The private key is used by programs (usually on your local computer) to connect to the remote server.


How to create a Public and Private Key on Linux

I usually run this command on Ubuntu or Debian Linux to generate a public and private SSH key.

sudo ssh-keygen -t rsa -b 4096

The key below was generated for this post and is not used online. Keys are like physical keys, people who have them and know where to use them can use them.

Output:

Generating public/private rsa key pair.
Enter file in which to save the key (/username/.ssh/id_rsa): ./server
Enter passphrase (empty for no passphrase): ********
Enter same passphrase again: ********
Your identification has been saved in ./server.
Your public key has been saved in ./server.pub.
The key fingerprint is:
SHA256:sxfcyn4oHQ1ugAdIEGwetd5YhxB8wsVFxANRaBUpJF4 username@server
The key's randomart image is:
+---[RSA 4096]----+
| .oB**E@Bo       |
|  +.==B.+        |
| o .o+o+..       |
|  .. +..o...     |
|    o ..Sooo.    |
|         ++o.    |
|        .o+o     |
|        .oo .    |
|         ...     |
+----[SHA256]-----+

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The two files were created

server
server.pub
  • server” is the private key
  • server.pub“is the public key

Public/Private Key Contents

Public Key Contents (“server.pub”)

ssh-rsa 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 username@servercom

Private Key Contents (“server”), always keep the private key safe and never publish it.

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-128-CBC,D34670C40CE3778974BEF97094010597
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c+y9lQUKbq2yDlxReCIsfb/hda5k1HjgaUlhKbjWIITSlGqf/NE9i+vj0rQEMQXQ
mxBoilfLUPd5A1ttG5XvqC2ex5HBmjzCazZ13Z/2c/PkwicHBmrf5bKYHZp49niV
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RJibaM/11MLTcZSO7KOK65Dg2v3VBhe6rfDl4tTR0yOySPXCacb9aMt2pMPTEe0/
wU49wCefchfD2bsR3kXPpUqm+HbkHORpIwsMZfQO/8dooXYdiYUdzV9roXG6OGVQ
SsV/xR2lE3XrR71TBegfRnQirI8tj4psSor+yCj3qV936Oh31D96Z6P4glshibsG
ffWAO/TSdu5ZV+UVahh6bTozs+g+odUu/S48TeI1fk7lPlqwZdjoSHXUI2v1FAQ2
jSSywuZQxHlGhg6OeI052cxx3zcVyVVLFHhIrfvufNc3c3+KYhtyiSzBNYN1BrJi
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Ojp4tY1tbI520KOskV/OoqEfmhXh5fTlIconzoK1aLqxk1d0d65ONcxqVbAG79RN
b0Q5PgewSOgFlcZ7tEIZKAWsWVhjlFTSGRujdZVM1vZB9fCJesemai7HU0e4J+Do
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exRgAnvUIhR/GpSySDDwgKHg8rAyjjoGeZFH3TJIemAAimyaR608a9tCn7SxVobs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-----END RSA PRIVATE KEY-----

The Public and Private keys used to encrypt all Telnet/SSH connections and traffic to your server. Keep these key’s private.

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fyi: Putty can create SSH Keys too

If you do not have a Linux computer or Linux server to generate keys the Putty generator can create keys too.

Puttygen generating a key based on the randomness of mouse movements.

I did not know Putty can create keys.

Do save the public and private key(s) that were generated in Puttygen (tip: PPK files are what we are after along with the public key later in this post).

Public keys are added to your server when you deploy them. On Linux, you can add new keys after deployment by adding them to this file “~/.ssh/authorized_keys” to allow people to log in.

Puttygen does format the keys differently than how Ubuntu generates them. Read more here. I’ll keep generating keys in Linux over Puttygen.

Output of the public and PPK files from Puttygen

Putty SSH Client on Windows

Putty is a free windows program that you can use to connect to serves via SSH. Download and install the Putty program.

Open Putty

Putty Icon

Default Putty User Interface.

Screenshot of the Putty Program

To create a connection add an exiting IP address (server name) and SSH port (22) to Putty.

Screenshot of an IP and port entered into putty

In Putty (note the tree view to the left of the image), You can set the auto login name to use to log into the remote server under the Connection the Data in the tree view item

Screenshot showing the SSH usename being added to putty under Connection then Data menu,

You can also set the username under the Connection then Rlogin section of Putty.

Set the usernmae undser rlogin area of putty

OK, lets add the private SSH Key to Putty.

Putty Screehshot showing no support for standard SSH keys (only PPK files)

It looks like Putty only supports PPK private key files not ones generated by Linux. I used to be able to use the private key in the VSSH program on OSX and add the private key to connect to the server over SSH. Putty does not allow you to use Linux generated Private keys directly.

Convert your (Linux generated) private key to (Putty) PPK format with Puttygen

Putty comes with a Key Generator/Converter, you can open your existing RSA private key and convert it (or generate a new one).

TIP: If you generate a key in Puttygen forget to ad’d it to your authorized host file in your remote server.

Open Puttygen

Puttygen icon

Click Conversions than Import Key and choose the private key you generated in Linux

Screenshot showing import RSA key to convert

The private key will be opened

Screenshot of imported RSA key

You can then save the private key as a PPK file.

Save the private key as a PPK file

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“server.ppk” Key contents
PuTTY-User-Key-File-2: ssh-rsa
Encryption: aes256-cbc
Comment: imported-openssh-key
Public-Lines: 12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Private-Lines: 28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Private-MAC: 12298fa865ac574da81898252e83b812200cba59

Now the PPK key can be added to Putty for any server connection that uses public key. Use the right key for the right server though.

Add the private key to a Putty server by clicking , SSH, AUTH section and to the PPK file.

Screenshot showing the PPK key file added to Putty

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Now we need to save the connection, click back on the Session note at the top of the , type a server name and click Save

Save Putty connection.

Connecting to your sever via Telnet/SSH Putty.

Once you have added a server name, port, usernames and private key to Putty you can double click the server list item to connect to your server.

You will see a message about accepting the public key from the server. Click Yes. This fingerprint will be the same fingerprint that was shown when you generated the keys (if not maybe someone is hacking in the middle of your local computer and server)

Putty messgae box asking to to remember the public key

Hopefully, you will now have full access to your server with the account you logged in with.

Screenshot of an Ubuntu screen after login

Happy Coding.

Alternatives to self-managed VM’s

I will always run server (and configure it myself) as its the most economical way to build a fast and secure server in my humble opinion.

I have blogged about alternatives but these solutions always sacrifice something and costs are usually higher and performance can be slower.

I am also lucky enough I can do this as a hobby and its not my day job. when you self manage a VM you will have endless tasks or securing your server and tweaking but its fun.

More Reading

Read some useful Linux commands here and read my past guides here. If you want to buy a domain name click here.

If you are bored and want to learn more about SSH Secure shell read this.

Related Blog Posts

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Version: Draft 1.0 Initial Draft

The post Connecting to a server via SSH with Putty appeared first on Code, InfoSec and Server Stuff.