RFC 101: What Is a Request for Comments?

Written by: Lizzie Danielson

Published: 6/28/2025

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A Request for Comments (RFC) is a public document describing technical rules, methods, or ideas about how the Internet works. RFCs set the standards for Internet protocols and cybersecurity practices.

RFCs are the official instruction manuals and blueprints for building the Internet and keeping it secure. They couldn't be more important—even if they've got a name that sounds a bit like a suggestion box. If you're new to cybersecurity or networking, you’ve definitely bumped into technology shaped by an RFC (even if you didn’t know it).

Let's break down what RFCs are, why they matter, and how they're the backbone of internet security.

What is a request for comments?

An RFC, or "Request for Comments," is a type of technical document published by folks who help set the rules of the internet, mainly the Internet Engineering Task Force (IETF). Think of it as the internet’s open-source playbook where anyone can read the rules, and experts from all over the globe can suggest improvements.

Here’s what makes RFCs stand out:

Publicly available (nothing’s hidden behind a paywall)
Authoritative (they become the foundation for networking and security standards)
Evolving (new RFCs get created as technology changes)

How RFCs shape the Internet

Picture the internet as a gigantic, worldwide Lego set. Every brick (like sending an email, streaming a video, or making a secure connection) needs to fit perfectly with every other brick. RFCs are the instruction manuals that say, “Hey, everyone needs to build their bricks this way for things to work together.”

RFCs define everything from how computers share files to how packets of data are secured as they zip across networks. They make sure the “language” computers use is universal, no matter the hardware or operating system.

RFCs matter in cybersecurity— here’s why

You might be wondering, “Okay, but how does RFC relate to cybersecurity?” The answer is simple:

Security standards and protocols (like HTTPS and encryption) are defined by RFCs.
When vulnerabilities or new types of attacks are discovered, new RFCs can introduce fixes or improvements.
Organizations rely on RFCs to know the best practices for building secure systems and teaching teams to spot weaknesses.

For example, the rules that tell browsers when to warn you about an unsafe site? Those are outlined in one or more RFCs.

Pro Tip: Want to understand how a security tool works (say, a firewall or VPN)? Look up its underlying RFCs for all the nitty-gritty details.

Breaking down the RFC process

Don’t worry, you don’t need a Ph.D. to follow along.

Step 1: Drafting the Idea.

A person or group writes up a “draft.” This explains their new idea, protocol, or fix.

Step 2: Community Review.

The draft gets shared with a working group (usually in the IETF) for detailed feedback. Everyone can suggest changes.

Step 3: Last Call for Comments.

The draft is published for a final round of public input. This is where anyone with thoughts can email their “comments.” (Now you see where the name comes from!)

Step 4: Review by Experts.

A committee (called the Internet Engineering Steering Group) double-checks for accuracy, completeness, and real-world usefulness.

Step 5: Official Publication.

If it gets a thumbs-up, the RFC Editor assigns it a permanent number and publishes it online. RFCs never change after publication, but new ones can replace outdated ones.

Fun Fact: The very first RFC, from 1969, was called “Host Software,” and it was just a short memo!

Types of RFCs you should know

Not all RFCs are set in stone, and not all of them are jam-packed with complex rules. Here’s a quick cheat sheet:

Standards track: These RFCs define official Internet protocols (like TCP/IP). They’re the backbone of how networks communicate.
Informational: These share ideas, suggestions, or background info, but they don’t create rules.
Experimental: Got a wild new idea? These RFCs test emerging technologies not quite ready to be a standard.
Best current practice (BCP): These outline recommended ways to stay safe, efficient, and up to date.
Historic: Oldies that helped the internet grow up—but aren’t in use anymore.

Famous RFCs That Changed the Game

RFC 791: Lays out the ground rules for the Internet Protocol (IP), aka the address system behind every device online.
RFC 793: Defines TCP, which ensures data arrives in the right order.
RFC 2616: Introduces HTTP/1.1, powering website communication.
RFC 5246: Describes TLS 1.2, the tech behind secure online shopping and banking.

Spot a technical standard on a website or in a help doc? There’s almost always an RFC number listed as the source.

Why should you care about RFCs as a cybersecurity professional

Every time you double-check a website’s URL for HTTPS, set up a home firewall, or implement multi-factor authentication, you’re using tools and knowledge grounded in RFCs. If you want to level up your career or simply keep your info safe, learning the basics of RFCs gives you backstage access to how internet security is built (and fixed).

Want to take it further?

Explore RFCs directly at the RFC Editor’s official site.

FAQs about RFCs

An RFC is a published document that outlines rules, standards, or concepts for networking technologies. It’s essential because it creates the universal standards that keep the internet running smoothly and securely.

Anyone can write and submit an RFC draft, but it must follow the process set by the Internet Engineering Task Force (IETF). Most final RFCs come from expert working groups.

Once published, an RFC doesn’t change. If updates are needed, a new RFC is created that references and replaces the old one. This keeps the historical record clean.

No, but many cover security protocols, best practices, and fixes for vulnerabilities, making them vital for anyone who cares about safe networking.

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RFC 101: What Is a Request for Comments?

Written by: Lizzie Danielson

Published: 6/28/2025

Summarize This Page

On This Page

Let's break down what RFCs are, why they matter, and how they're the backbone of internet security.

What is a request for comments?

Here’s what makes RFCs stand out:

Publicly available (nothing’s hidden behind a paywall)
Authoritative (they become the foundation for networking and security standards)
Evolving (new RFCs get created as technology changes)

How RFCs shape the Internet

RFCs matter in cybersecurity— here’s why

You might be wondering, “Okay, but how does RFC relate to cybersecurity?” The answer is simple:

Security standards and protocols (like HTTPS and encryption) are defined by RFCs.
When vulnerabilities or new types of attacks are discovered, new RFCs can introduce fixes or improvements.
Organizations rely on RFCs to know the best practices for building secure systems and teaching teams to spot weaknesses.

For example, the rules that tell browsers when to warn you about an unsafe site? Those are outlined in one or more RFCs.

Pro Tip: Want to understand how a security tool works (say, a firewall or VPN)? Look up its underlying RFCs for all the nitty-gritty details.

Breaking down the RFC process

Don’t worry, you don’t need a Ph.D. to follow along.

Step 1: Drafting the Idea.

A person or group writes up a “draft.” This explains their new idea, protocol, or fix.

Step 2: Community Review.

The draft gets shared with a working group (usually in the IETF) for detailed feedback. Everyone can suggest changes.

Step 3: Last Call for Comments.

The draft is published for a final round of public input. This is where anyone with thoughts can email their “comments.” (Now you see where the name comes from!)

Step 4: Review by Experts.

A committee (called the Internet Engineering Steering Group) double-checks for accuracy, completeness, and real-world usefulness.

Step 5: Official Publication.

If it gets a thumbs-up, the RFC Editor assigns it a permanent number and publishes it online. RFCs never change after publication, but new ones can replace outdated ones.

Fun Fact: The very first RFC, from 1969, was called “Host Software,” and it was just a short memo!

Types of RFCs you should know

Not all RFCs are set in stone, and not all of them are jam-packed with complex rules. Here’s a quick cheat sheet:

Standards track: These RFCs define official Internet protocols (like TCP/IP). They’re the backbone of how networks communicate.
Informational: These share ideas, suggestions, or background info, but they don’t create rules.
Experimental: Got a wild new idea? These RFCs test emerging technologies not quite ready to be a standard.
Best current practice (BCP): These outline recommended ways to stay safe, efficient, and up to date.
Historic: Oldies that helped the internet grow up—but aren’t in use anymore.

Famous RFCs That Changed the Game

RFC 791: Lays out the ground rules for the Internet Protocol (IP), aka the address system behind every device online.
RFC 793: Defines TCP, which ensures data arrives in the right order.
RFC 2616: Introduces HTTP/1.1, powering website communication.
RFC 5246: Describes TLS 1.2, the tech behind secure online shopping and banking.

Spot a technical standard on a website or in a help doc? There’s almost always an RFC number listed as the source.

Why should you care about RFCs as a cybersecurity professional

Want to take it further?

Explore RFCs directly at the RFC Editor’s official site.

FAQs about RFCs

Anyone can write and submit an RFC draft, but it must follow the process set by the Internet Engineering Task Force (IETF). Most final RFCs come from expert working groups.

Once published, an RFC doesn’t change. If updates are needed, a new RFC is created that references and replaces the old one. This keeps the historical record clean.

No, but many cover security protocols, best practices, and fixes for vulnerabilities, making them vital for anyone who cares about safe networking.

Additional Resources

Read more about What Is Access Logging? How to Read Access Logs
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Learn what cloud networking is, the benefits of secure cloud networking, and the different types of cloud. See what’s best for your business.
Read more about What is the Data Plane? Data Plane Vs Control Plane
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Learn about the data plane in networking - the component that forwards data packets. Understand cybersecurity implications and best practices for protection.
Read more about What Is Post Office Protocol (POP3)? Security Guide
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Learn what Post Office Protocol is, how POP3 works, its security risks, and why cybersecurity pros must know it. Discover best practices and FAQs.
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Read more about What is Security Misconfiguration?
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Read more about What is a Domain Admin Group? Best Cybersecurity Practices
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RFC 101: What Is a Request for Comments?

What is a request for comments?

How RFCs shape the Internet

RFCs matter in cybersecurity— here’s why

Breaking down the RFC process

Types of RFCs you should know

Famous RFCs That Changed the Game

Why should you care about RFCs as a cybersecurity professional

FAQs about RFCs

What is an RFC and why is it important in networking?

Who can submit an RFC?

How do changes happen to an existing RFC?

Are all RFCs about cybersecurity?

Additional Resources

Protect What Matters

RFC 101: What Is a Request for Comments?

What is a request for comments?

How RFCs shape the Internet

RFCs matter in cybersecurity— here’s why

Breaking down the RFC process

Types of RFCs you should know

Famous RFCs That Changed the Game

Why should you care about RFCs as a cybersecurity professional

FAQs about RFCs

What is an RFC and why is it important in networking?

Who can submit an RFC?

How do changes happen to an existing RFC?

Are all RFCs about cybersecurity?

Additional Resources

Protect What Matters