How I Connected to My EC2 Instance via SSH (macOS & Windows)

So, after launching my first EC2 instance yesterday (still feels cool to say that 😄), I realized the next thing I needed to do was connect to it. I’d heard the term SSH before, but I hadn’t used it much. This part felt a bit intimidating at first — but turns out, it wasn’t that bad.

Here’s how I did it.

Step 1: Found My PEM File and Public IP

AWS gave me a .pem file when I launched the instance. I had saved it in a folder on my desktop. I also noted down the public IP of the instance from the EC2 dashboard — without it, I wouldn't know where to connect.

Since I’m on macOS, I Tried the Terminal First

I opened the Terminal app and went to the folder where my .pem file was.

cd ~/Desktop/aws-stuff

But then the first issue hit me — permission denied. I Googled it, and turns out I had to restrict access to the key file. So I ran:

chmod 400 my-key.pem

That did the trick.

Then I tried connecting:

ssh -i "my-key.pem" ec2-user@<EC2_PUBLIC_IP>

Boom 💥 — I was in! It felt amazing seeing that EC2 shell prompt.

Then I Tested It on Windows (For Practice)

I also wanted to try this from my Windows laptop, just to see how different it is.

The .pem file doesn’t work directly with PuTTY, so I had to convert it using PuTTYgen. At first I didn’t know this, so I downloaded PuTTY and wondered why it wouldn’t accept my key.

So I did this:

Opened PuTTYgen
Loaded the .pem file (had to select “All Files” to see it)
Clicked Save private key, and it gave me a .ppk file

Then, in PuTTY:

I entered my EC2 public IP as the hostname:
ec2-user@<EC2_PUBLIC_IP>
In the SSH > Auth section, I browsed for my .ppk file

When I hit Open, it asked me to trust the server (clicked Yes), and then I was inside the EC2 instance. It worked on Windows too!

A Few Things That Tripped Me Up

The permission thing on macOS was weird at first. That chmod 400 command saved me.
On Windows, I didn’t know PuTTY needed a .ppk key instead of .pem.
I almost forgot to open port 22 in the security group. Luckily, I had read somewhere about SSH needing it. I added a rule to allow SSH from my IP.

What I Learned 🧠

This whole process taught me a few cool things:

SSH is actually not that scary
AWS doesn’t let you re-download the key, so saving the .pem file properly is super important
The same EC2 instance can be accessed from macOS and Windows with the right steps

What’s Next?

Now that I can connect to my EC2 instance, I want to try setting up a simple web server on it — maybe NGINX or Apache, just to see how it works. That’s probably going to be my Day 3 blog.

Day 2. AWS - EC2