Linux Networking
IP addressing, interfaces, routing tables, DNS and name resolution. Understand how traffic gets from A to B, and why it sometimes takes an unscheduled holiday.
Packets. Permissions. Peace of mind.
Networking.
Security.
Less mystery.
Networks are wonderful things. They let computers talk to each other, share useful information, and occasionally spend an entire afternoon refusing to connect for reasons known only to themselves. We explore Linux networking, SSH, firewalls, access controls, system hardening and the fine art of finding out what went wrong.
Linux · SSH · Firewalls · Hardening · Routing · Access control
SSH keys
Firewall
Routing & DNS
Least privilege
ALLOW WHAT YOU NEED ✳ DENY WHAT YOU DON'T ✳ LOG WHAT MATTERS
The network behind the curtain
Connected doesn't always mean secure.
A practical look at the tools, techniques and decisions that help keep systems reachable by the right people — and rather less interesting to everyone else.
SSH & Remote Access
Public-key authentication, sensible SSH configuration, user restrictions and port forwarding. Remote access is useful; inviting the entire internet to try your passwords is less so.
Firewalls & Segmentation
Host firewall policies, network separation and least privilege. Give services the connectivity they need without granting every packet an all-access backstage pass.
System Hardening
Secure defaults, authentication, permissions, updates, logging and reducing unnecessary services. Fewer open doors mean fewer doors that need guarding.
Troubleshooting
Check routes, listening ports, firewall rules, DNS and logs. Follow the evidence rather than changing six things at once and hoping the gremlins take the hint.
Secure Infrastructure
Linux and Proxmox network design, management access, trust boundaries and security reviews. Build systems that are understandable, maintainable and appropriately cautious.
A few useful principles
Security is a process, not a magic spell.
No single firewall rule, SSH setting or shiny product makes a system invulnerable. Good security comes from sensible layers, clear decisions and regular maintenance.
- Least privilege Give users and services only the access they actually need.
- Reduce the attack surface Disable unnecessary services and avoid exposing management interfaces without a good reason.
- Log and review Useful logs help turn mysterious behaviour into something that can be investigated.
- Plan for recovery Updates, tested backups and a recovery plan matter just as much as preventative controls.
# Show listening sockets
ss -tulpn
# Check the route to a destination
ip route get 192.0.2.10
# Check the SSH service
systemctl status ssh
# Inspect firewall rules
sudo ufw status verboseExamples for exploration, not a substitute for understanding your own system. Please don't paste random commands into production and hope the security gremlins are friendly.
A message from the mysterious headquarters
Something not connecting?
Something connecting too much?
Whether you're investigating a Linux networking puzzle, tightening up remote access or simply trying to understand what your firewall is doing, you're in the right place.
No secret handshake required. A reasonably well-formed question will usually do.
Contact WorldHQ ↗