12 myths about how the Internet works

A list of assumptions we make when we hit the send button or download a video

8. New transport-layer protocols will work across the Internet

IP was designed to support new transport protocols underneath it, but increasingly this isn't true, Thaler says. Most NATs and firewalls only allow Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) for transporting packets. Newer Web-based applications only operate over Hypertext Transfer Protocol (HTTP).

9. If one stream between you and me can get through, so can another one

Some applications open multiple connections -- one for data and another for control -- between two systems for communications. The problem is that middle-boxes such as NATs and firewalls block certain ports and may not allow more than one connection. That's why applications such as File Transfer Protocol (FTP) and the Real-time Transfer Protocol (RTP) don't always work, Thaler says.

10. Internet communications are not changed in transit

Thaler cites several assumptions about Internet security that are no longer true. One of them is that packets are unmodified in transit. While it may have been true at the dawn of the Internet, this assumption is no longer true because of NATs, firewalls, intrusion-detection systems and many other middle-boxes. IPsec solves this problem by encrypting IP packets, but this security scheme isn't widely used across the Internet.

11. Internet communications are private

Another security-related assumption Internet developers and users often make is that packets are private. Thaler says this was never true. The only way for Internet users to be sure that their communications are private is to deploy IPsec, which is a suite of protocols for securing IP communications by authenticating and encrypting IP packets.

12. Source addresses are not forged

Many Internet applications assume that a packet is coming from the IP source address that it uses. However, IP address spoofing has become common as a way of concealing the identity of the sender in denial of service and other attacks. Applications built on this assumption are vulnerable to attack, Thaler says.

Join the newsletter!


Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags wireless lan

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Carolyn Duffy Marsan

Network World
Show Comments

Most Popular Reviews

Latest Articles


PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers


This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang


It really doesn’t get more “gaming laptop” than this.

Jack Jeffries


As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr


The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?