A categorized cheat sheet of common networking, security, and web protocols, grouped by what they're used for rather than alphabetically.
Protocols used to connect to and control systems from elsewhere on a network.
| Protocol | Acronym | Description |
|---|---|---|
| Secure Shell | SSH | Securely logs into and runs commands on a remote system over an encrypted connection. |
| Virtual Private Network | VPN | Creates a secure, encrypted connection to another network over the internet. |
| Point-to-Point Tunneling Protocol | PPTP | Creates a secure, encrypted tunnel for remote access. |
| Remote Shell | RSH | A Unix program that lets you run commands on a remote computer (unencrypted, largely obsolete). |
Protocols for moving or accessing files between systems.
| Protocol | Acronym | Description |
|---|---|---|
| File Transfer Protocol | FTP | Transfers files between systems over a network. |
| Server Message Block | SMB | Shares files, printers, and other resources across a network (common on Windows). |
| Network File System | NFS | Lets systems access and share files over a network (common on Unix/Linux). |
Protocols behind email delivery and live voice/video sessions.
| Protocol | Acronym | Description |
|---|---|---|
| Simple Mail Transfer Protocol | SMTP | Sends and receives email between mail servers. |
| Network News Transfer Protocol | NNTP | Distributes and retrieves messages in Usenet newsgroups. |
| Session Initiation Protocol | SIP | Signaling protocol that sets up and tears down real-time voice, video, and multimedia sessions. |
| Voice Over IP | VoIP | Allows phone calls to be made over the internet instead of traditional phone lines. |
Protocols and addressing schemes that power how browsers and servers talk.
| Protocol | Acronym | Description |
|---|---|---|
| Hypertext Transfer Protocol | HTTP | Client-server protocol used to send and receive data over the web. |
| Uniform Resource Identifier | URI | Generic syntax used to identify a resource on the internet. |
| Uniform Resource Locator | URL | A type of URI that points to a web page or resource, including protocol and domain name. |
| Asynchronous JavaScript and XML | AJAX | Technique for building dynamic web pages using JavaScript with XML/JSON data. |
| Internet Server Application Programming Interface | ISAPI | API set for building high-performance extensions for web servers. |
| Carriage Return Line Feed | CRLF | Two control characters marking the end of one line and the start of the next in text formats. |
Protocols protecting Wi-Fi networks and authenticating wireless clients.
| Protocol | Acronym | Description |
|---|---|---|
| Wired Equivalent Privacy | WEP | An early, now largely broken, protocol for securing wireless networks. |
| Wi-Fi Protected Access | WPA | Wireless security protocol that uses a password to protect Wi-Fi networks. |
| Temporal Key Integrity Protocol | TKIP | A wireless encryption protocol, weaker than modern alternatives. |
| Lightweight Extensible Authentication Protocol | LEAP | Cisco's proprietary wireless authentication protocol, based on EAP. |
| Protected Extensible Authentication Protocol | PEAP | Provides an encrypted tunnel to protect authentication on wireless and other networks. |
| Extensible Authentication Protocol | EAP | A flexible framework supporting multiple authentication methods (passwords, certificates, etc.). |
Protocols providing encryption and secure tunnels, often combined for VPNs.
| Protocol | Acronym | Description |
|---|---|---|
| Internet Protocol Security | IPsec | Provides secure, encrypted communication over a network; commonly used to build VPN tunnels. |
| Internet Key Exchange | IKE | Sets up a secure, authenticated connection between two computers, often for VPNs. |
| Generic Routing Encapsulation | GRE | Encapsulates data being sent through a VPN tunnel. |
| Pretty Good Privacy | PGP | Encryption program used to secure emails, files, and other data. |