SSH Key Management and Troubleshooting on RHEL

SSH Key Management and Troubleshooting on RHEL

Introduction

This tutorial aims to provide a comprehensive guide on managing SSH keys, setting the correct permissions, and troubleshooting common issues on a Red Hat Enterprise Linux (RHEL) system.

SSH Key Components

id_rsa and id_rsa.pub

• id_rsa: This is your private key. Keep it secure and never share it.
• id_rsa.pub: This is your public key. You can safely share it with others.

Setting Permissions

.ssh Directory

• Directory Permissions: 700
• Owner: The user who owns the home directory
• Group: Usually the primary group of the user

Commands:

chown username:username ~/.ssh
chmod 700 ~/.ssh

authorized_keys File

• File Permissions: 600

Commands:

chown username:username ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys

id_rsa and id_rsa.pub Files

• id_rsa File Permissions: 600
• id_rsa.pub File Permissions: 644

Commands:

chmod 600 ~/.ssh/id_rsa
chmod 644 ~/.ssh/id_rsa.pub

Generating SSH Keys

To generate SSH keys, you can use the ssh-keygen command:

ssh-keygen -t rsa -b 4096

Copying Keys to a Remote Server

You can use the ssh-copy-id command to copy your public key to a remote server:

ssh-copy-id username@remote-server

Troubleshooting

SELinux

If you encounter issues, SELinux could be a factor. On RHEL, you may need to set it to Permissive mode.

Commands:

setenforce 0
sestatus

Note: This is not recommended for production systems.

Conclusion

This tutorial should provide you with the knowledge to manage SSH keys effectively on a RHEL system.