4.10 Networking

22 entries match these filters

• 0449 Nmap: the network mapper for inventorying your own network Nmap is the long-standing open source tool for discovering hosts, open ports, services and operating systems on a network you administer, used… Linux, macOS, Windows Repo DNS, IP addresses & ports · Security testing & CTF 15 Oct 2026
• 0435 CrowdSec: collaborative intrusion prevention that shares blocklists CrowdSec reads your logs, detects attacks such as brute force and scanning, blocks the source, and shares anonymised reports so that every… Linux, Windows Repo Detection & threat hunting · Firewalls 15 Oct 2026
• 0436 Suricata: a network intrusion detection and prevention engine Suricata inspects network traffic in real time, matches it against signature rules and protocol logic, and writes alerts and rich protocol logs.… Linux Repo Detection & threat hunting · Firewalls 15 Oct 2026
• 0358 SSH server audit script: print risky sshd settings A read-only bash script that asks sshd for its effective configuration, compares the important settings with safe values, flags config.d files that… Intermediate · Cheat sheet · Linux Script Server hardening · SSH 15 Oct 2026
• 0359 fail2ban: ban hosts that fail to log in too often The standard intrusion-prevention daemon on Linux servers: it watches logs or the journal for repeated failures and adds temporary firewall rules against… Linux Repo Server hardening · SSH 15 Oct 2026
• 0349 Set up a WireGuard VPN with wg-easy in Docker Run a WireGuard server with a web admin page on one Linux host, open the UDP port, add a client from the… Intermediate · Guided project · Linux Article Networking & firewalls · VPN & tunnels 15 Oct 2026
• 0350 wg-easy: WireGuard VPN with a web admin interface A Docker image that runs a WireGuard server and a web page to create clients, show QR codes and watch traffic. The… Linux Repo VPN & tunnels 15 Oct 2026
• 0347 Port check script: test a list of host:port pairs with timeouts A bash script that tries a TCP connection to each host:port you give it, waits a few seconds at most, and reports… Beginner · Cheat sheet · Linux, macOS Script DNS, IP addresses & ports · Firewalls 15 Oct 2026
• 0348 DNS check script: compare answers from several resolvers A bash script that looks up one or more names against your system resolver and three public resolvers, shows each answer with… Beginner · Cheat sheet · Linux, macOS Script DNS, IP addresses & ports 15 Oct 2026
• 0351 Pi-hole: network-wide ad blocking with your own DNS server A DNS server for your home or office network that answers queries for known advertising and tracking domains with nothing, so every… Linux Repo DNS, IP addresses & ports · VPN & tunnels 15 Oct 2026
• 0344 ufw and firewalld: open and close ports Allow and remove ports and services on the two standard Linux host firewalls, restrict a port to one source network, and make… Beginner · Step by step · Linux Article Firewalls · Networking & firewalls 15 Oct 2026
• 0345 SSH keys: create, copy and use them Generate an ed25519 key pair, install the public key on a server with ssh-copy-id, keep the private key protected with a passphrase… Beginner · Step by step · Linux, macOS, Windows Article Keys & config · SSH 15 Oct 2026
• 0346 The SSH config file: aliases, jump hosts and keys per server Reference for ~/.ssh/config: short names for servers, the right user, port and key per host, ProxyJump through a bastion, connection reuse and… Intermediate · Cheat sheet · Linux, macOS, Windows Article Keys & config · SSH 15 Oct 2026
• 0353 fail2ban: block repeated failed logins Install fail2ban, enable the sshd jail with sane ban times, whitelist your own address, read the ban list, unban someone, and add… Intermediate · Step by step · Linux Article Server hardening · SSH 15 Oct 2026
• 0341 DNS, IP addresses and ports explained for beginners An IP address says which machine, a port says which program on it, and DNS turns names into addresses. The three ideas… Beginner · Explains an idea · Linux, macOS Article DNS, IP addresses & ports 15 Oct 2026
• 0342 Which process is using a port, and how to free it Find the program behind a busy port with ss, lsof or fuser, decide whether to stop it properly or kill it, and… Beginner · Step by step · Linux, macOS Article DNS, IP addresses & ports · Networking & firewalls 15 Oct 2026
• 0343 Fix: Connection refused and Connection timed out, what each one means Refused means the host answered and nothing is listening there. Timed out means no answer at all, usually a firewall or wrong… Beginner · Fixes an error · Linux, macOS Article DNS, IP addresses & ports · Firewalls 15 Oct 2026
• 0275 What is an IP address? An IP address is the unique number that identifies a device on a network so data knows where to go. Beginner · Explains an idea · Any system Article DNS, IP addresses & ports 15 Oct 2026
• 0280 What is a firewall? A firewall is a filter that decides which network connections are allowed in or out of a computer or network. Beginner · Explains an idea · Any system Article Firewalls 15 Oct 2026
• 0276 What is SSH? SSH is a secure way to open a command line on another computer over the network, with everything encrypted. Beginner · Explains an idea · Any system Article SSH 15 Oct 2026
• 0266 What is a port? A port is a numbered door on a computer that lets one machine run many network services at the same time. Beginner · Explains an idea · Any system Article DNS, IP addresses & ports 15 Oct 2026
• 0274 What is DNS? DNS is the internet's phone book: it turns names like example.com into the IP addresses computers actually use. Beginner · Explains an idea · Any system Article DNS, IP addresses & ports 15 Oct 2026