
Hi !
When you test and play around with your Raspberry Pi, you may need to format again your Raspbian SD Card, and then start everything from scratch. This is a trivial process, and is usual to setup the device to connect automatically to a Wifi network and also enable SSH (I wrote about this, see references).
And then, when you try to connect via SSH you may get this warning
C:\Users\bruno> ssh pi@192.168.1.247 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that a host key has just been changed. The fingerprint for the ECDSA key sent by the remote host is SHA256: Not here ! Please contact your system administrator. Add correct host key in C:\\Users\\bruno/.ssh/known_hosts to get rid of this message. Offending ECDSA key in C:\\Users\\bruno/.ssh/known_hosts:10 ECDSA host key for 192.168.1.247 has changed and you have requested strict checking. Host key verification failed.

This is a very common scenario, and because I forgot how to fix it, I’ll write the simple command remove all keys belonging to the IP / hostname from the known_hosts file.
# ssh-keygen -R <host> ssh-keygen -R 192.168.1.247
And that’s it, keys removed and now I can connect via SSH

Happy coding!
Greetings
El Bruno
References
My posts on Raspberry Pi β‘π²β‘
Dev posts for Raspberry Pi
- How to grant permissions to a folder after git clone, to perform dotnet restore on a Raspberry Pi
- How to install .Net Core 3.1 in a Raspberry Pi 4
- Installing Visual Studio Code in a Raspberry Pi 4, run as root, fix black screen
- How to install .Net Core in a Raspberry Pi 4 and test with Hello World
- Build and Run C# NetCore projects in a Raspberry Pi 4 with Visual Studio Code
- Letβs do some Git dev in Raspberry Pi 4 (GitHub and Azure DevOps!)
- Install OpenCV
- Install Python π Virtual Environments in Raspberry Pi
- Setup SSH passwordless access to remote work with Docker π³
- Manage Docker π³ as a non-root user
- Build Docker π³ images from Visual Studio Code remotely using a Raspberry Pi
Tools and Apps for Raspberry Pi
- Where is my Task Manager in RaspberryPi? Letβs try htop
- Multi-monitor πΊ in Raspberry Pi 4 rocks !
- Double Commander on RaspberryPi4, because files are important
- How to install Docker π³ in a Raspberry Pi 4
- Installing Visual Studio Code in a Raspberry Pi
- Installing Visual Studio Code in a Raspberry Pi, run as root, fix black screen (Updated)
- 6 commands to install OpenCV for Python π in a Raspberry Pi 4
Setup the device
- 1st Setup without monitor πΊ: auto connect to WiFi πΆ, enable SSH, update and more
- Setup without monitor: enable VNC
- How to enable auto start with HDMI safe mode
- Running a Python π script in a Python Virtual Environment on reboot / startup
- Setup Wifi on Ubuntu
Hardware
- Ice Tower, the best cooler π§ for your device! From 70C to <40C in a 60 minutes process running at 100% in all 4 cores
- Intel Neural Stick 2, Performance differences in Face Recognition using OpenVino
Azure IoT
- Install β Azure IoT on Raspberry Pi
- Deploy β Azure Blob Storage on IoT Edge, lessons learned
- Connect to β Azure Blob Storage on IoT Edge using Microsoft Azure Storage Explorer
- Lesson learned and tips on how to install Azure IoT Edge on Ubuntu on a Raspberry Pi
- Azure IoT Explorer, in preview and awesome