ssh
Secure Shell protocol for secure remote connections and authentication
Resolve SSH 'Permissions 0777 for id_rsa are too open' error. Set correct permissions: chmod 600 ~/.ssh/id_rsa, 700 ~/.ssh on Linux/macOS. Windows icacls fix included. Secure private keys properly.
Resolve 'Warning: Remote Host Identification Has Changed!' error in GitHub SSH from 2023 RSA key update. Step-by-step fix: ssh-keygen -R github.com, ssh-keyscan to add new keys, verify with ssh -T git@github.com for git push/clone.
Troubleshoot and fix Debian 12 WiFi dropping idle connections causing SSH disconnects and Apache unreachability. Disable wifi power save, configure NetworkManager, add SSH keepalives for reliable home server on WiFi.
Diagnose Raspberry Pi 4 green ACT LED blinking: bootloader, SD/USB, EEPROM checks, power tests, serial logs and recovery steps to restore boot and SSH.
Step-by-step guide to set up RDP access to home PC (192.168.0.20:3389) through VPS proxy (200.1.1.1) using SSH tunnel on Raspberry Pi. Fix iptables, AllowTcpForwarding, GatewayPorts, and verify forwarding.