SSH basics for Indian VPS users: connecting and navigating your server

SSH (Secure Shell) is the terminal you use to control a Linux VPS. Every server management task — installing software, editing config files, checking logs, deploying code — happens here. Here is everything you need to get started.

What SSH is

SSH gives you a command-line terminal on a remote server. It is like sitting in front of the server — but over an encrypted connection from your laptop.

The SSH connection uses port 22 by default and authenticates with either:

• A password (simple but less secure)
• An SSH key pair (recommended)

Connecting from Windows

Option A: Windows Terminal / PowerShell (Windows 10+) Windows now includes a built-in SSH client. Open Windows Terminal or PowerShell:

ssh username@your-server-ip

Example:

ssh root@103.56.89.234

Type yes when asked about the host fingerprint. Enter your password.

Option B: PuTTY (traditional, still widely used) Download PuTTY from putty.org. Enter your server IP in "Host Name", keep port 22, click Open.

Connecting from Mac or Linux

Open Terminal and run:

ssh username@your-server-ip

Setting up SSH key authentication (more secure than passwords)

SSH keys eliminate the need to type a password and are much more secure.

Step 1: Generate a key pair on your local machine

On Mac/Linux/Windows Terminal:

ssh-keygen -t ed25519 -C "your-email@example.com"

Press Enter for the default location (~/.ssh/id_ed25519). Set a passphrase if you want extra security.

This creates two files:

• ~/.ssh/id_ed25519 — your private key (never share this)
• ~/.ssh/id_ed25519.pub — your public key (safe to share)

Step 2: Copy the public key to the server

Mac/Linux:

ssh-copy-id username@your-server-ip

Windows (manual):

# Get the public key content
cat ~/.ssh/id_ed25519.pub

Log into the server with password, then:

mkdir -p ~/.ssh
echo "paste_your_public_key_here" >> ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys
chmod 700 ~/.ssh

Step 3: Test key-based login

ssh username@your-server-ip

If it connects without asking for a password, key authentication is working.

Essential Linux commands

Once connected, you are at a command-line prompt. The most important commands:

Navigation:

pwd              # print working directory (where am I?)
ls               # list files in current directory
ls -la           # list files including hidden files, with details
cd /path/to/dir  # change directory
cd ..            # go up one directory
cd ~             # go to your home directory

File operations:

cat filename.txt        # view file contents
nano filename.txt       # edit a file (simpler editor)
vim filename.txt        # edit a file (more powerful editor)
cp source dest          # copy file
mv source dest          # move or rename file
rm filename             # delete file (permanent, no trash!)
rm -rf directoryname    # delete directory and all contents (dangerous!)
mkdir dirname           # create directory

Process management:

ps aux              # list all running processes
top                 # interactive process viewer (press q to quit)
htop                # better interactive process viewer (install with apt)
kill PID            # send SIGTERM to process ID
kill -9 PID         # force-kill process

Package management (Ubuntu/Debian):

sudo apt update               # update package list
sudo apt upgrade              # upgrade installed packages
sudo apt install nginx        # install a package
sudo apt remove nginx         # remove a package

Services:

sudo systemctl status nginx    # check service status
sudo systemctl start nginx     # start service
sudo systemctl stop nginx      # stop service
sudo systemctl restart nginx   # restart service
sudo systemctl enable nginx    # start automatically on reboot

Disk and memory:

df -h              # disk usage (human-readable)
du -sh /var/www    # size of a specific directory
free -h            # memory usage

Viewing logs:

tail -f /var/log/nginx/error.log   # stream log file (Ctrl+C to stop)
tail -n 100 /var/log/syslog       # last 100 lines of syslog
grep "error" /var/log/nginx/error.log  # search log for "error"

Creating and managing users

Create a non-root user (always do this on a fresh VPS):

adduser yourname
usermod -aG sudo yourname  # give sudo access

Switch user:

su - yourname

Run a command as root:

sudo command

Transferring files via SCP

SCP (Secure Copy) transfers files over SSH.

Download file from server to local:

scp username@your-server-ip:/path/to/file ~/local/destination/

Upload file from local to server:

scp ~/localfile.zip username@your-server-ip:/path/on/server/

Upload entire folder:

scp -r ~/local-folder username@your-server-ip:/path/on/server/

For large or ongoing transfers, rsync is more efficient:

rsync -avz ~/local-folder/ username@your-server-ip:/path/on/server/

Keeping your SSH session alive

Long SSH sessions disconnect if idle. Fix on the server side:

Edit /etc/ssh/sshd_config:

ClientAliveInterval 60
ClientAliveCountMax 10

Restart SSH: sudo systemctl restart sshd

Or on the client side, add to ~/.ssh/config:

Host *
    ServerAliveInterval 60

Securing SSH

Change the default port (reduces bot scanning):

Edit /etc/ssh/sshd_config:

Port 2222  # or any port above 1024

Update UFW: sudo ufw allow 2222/tcp (before restarting SSH)

Connect with: ssh -p 2222 username@your-server-ip

Disable root login:

PermitRootLogin no

Always create a non-root user with sudo access first.

Disable password authentication (use keys only):

PasswordAuthentication no

Only do this after confirming key-based login works. Otherwise you will lock yourself out.

After any sshd_config changes:

sudo systemctl restart sshd

Common SSH errors

"Connection refused": SSH is not running, or you are connecting to the wrong port. Check with your hosting provider.

"Permission denied (publickey)": Key authentication failed. Verify the public key is in ~/.ssh/authorized_keys on the server, and that permissions are correct (600 for the file, 700 for the .ssh directory).

"Host key verification failed": The server's fingerprint changed (happens after a server reinstall). Remove the old key: ssh-keygen -R your-server-ip

Disconnects after 5–10 minutes idle: Set ServerAliveInterval 60 in your SSH client config.