POP3 was built for a world where your computer didn't view your email—it became your email. Here's why that model still makes sense sometimes, and why port 110's naked simplicity is both its appeal and its danger.
Time isn't data your computer has—it's a consensus it maintains with the rest of the world. Port 123 and NTP are how billions of devices agree on when 'now' is.
IMAP transformed email from something trapped on one computer into something you could reach from anywhere. Here's how port 143 makes that possible—and why you should never use it without encryption.
FTP's two-port design made sense when the Internet was a network of trusted machines. Then firewalls arrived, and a protocol that expects servers to call clients back stopped working.
Before SSH, every password you typed crossed the network in plaintext. Port 22 changed everything—enabling encrypted remote access, secure file transfers, and tunnels that keep your secrets invisible to anyone listening.
Telnet let administrators control remote machines by sending every keystroke—including passwords—as readable text across the Internet. Here's why that was fine in 1969 and disastrous today.
Port 25 was email's open door until spammers walked through it. Now ISPs block it for users while servers still rely on it to talk to each other.
MongoDB's default port became the Internet's most expensive lesson in database security when attackers wiped thousands of unprotected databases and left ransom notes behind.
Port 3306 is the door to your application's memory. Every query, credential, and piece of data flows through it—which is exactly why attackers scan for it constantly.
RDP on port 3389 gives attackers complete control of Windows systems—and millions of organizations expose it directly to the Internet. Here's why that's catastrophic and how to fix it.
Port 443 is how we made privacy the default on a network built for openness—the story of HTTPS becoming the Internet's universal expectation.
Port 465 was killed in 1998 and resurrected in 2018. Port 587 was the official replacement nobody fully adopted. Here's what actually happened—and which port to use now.
Port 53 carries every DNS query your device makes—the invisible first step before any connection happens. How it works, how it breaks, and why it's moving toward encryption.
Port 5432 is the single door through which all PostgreSQL traffic flows. Understanding pg_hba.conf, SSL/TLS, and connection pooling determines whether that door is guarded or wide open.
Redis was built for trusted networks that assumed firewalls meant safety. That assumption broke, and port 6379 became one of the most exploited doors on the Internet.
To speak on a network, you need an address. To get an address, you need to speak. DHCP solves this impossible problem using two ports and a four-step dance that happens billions of times daily.
Port 80 was the front door to the web for two decades. Now it mostly exists to tell you to use the other entrance.
Port 8080 exists because Unix won't let unprivileged users bind to port 80. That single constraint shaped how we build development servers, reverse proxies, and containerized applications.
Port 993 encrypts your email connection before a single byte is exchanged. Port 143 with STARTTLS hopes to upgrade after the conversation starts. That difference is everything.
Port 995 wraps POP3 in TLS encryption from the first byte. Your credentials never travel in the clear, and your emails download to your machine rather than living on someone else's server.
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