Networking

How to SSH Into a Linux Server

Connect to a Linux server from Windows, macOS, or Linux. Use the right SSH command, verify the host key, and diagnose common login errors.

SSH Config File Examples: Set Up and Verify Host Profiles

Create SSH host aliases, select the intended key, understand config precedence, and inspect effective settings with ssh -G before debugging a connection.

How to Use ssh-copy-id and Verify SSH Key Login

Install the right SSH public key with ssh-copy-id, choose the correct user and port, verify which key authenticates, and recover from failed installation.

How to Fix SSH Permission Denied (publickey)

Fix SSH Permission denied (publickey) by reading debug output, checking client keys and server authorization, and finding a safe recovery route when locked out.

SCP Command in Linux: Copy Files, Directories, and Troubleshoot Errors

Use SCP to upload, download, and copy directories over SSH. Learn ports, keys, remote paths, checksum checks, permission fixes, and when to use rsync.

How to Use SFTP on Linux: Commands, SSH Keys, and Transfer Fixes

Connect with Linux SFTP, upload and download files, choose the correct SSH key, and distinguish connection, permissions, and batch-transfer failures.

How to Check Listening Ports and Processes in Linux

Use ss and lsof to find Linux port owners, read TCP and UDP socket states, and distinguish local listeners from remote access and Docker port mappings.

How to Diagnose Linux Network Problems with Ping, Traceroute, DNS, and Curl

Diagnose Linux connection problems with ping, traceroute, DNS checks, and curl. Learn what to test when results disagree and how to verify the original failure.