Telnet vs SSH – Difference, Security, Ports & Real-Life Examples (Beginner Guide)
You are a Network Engineer working in the Mumbai Office, and your boss says, “We need to update the hostname on our router in the USA Office. Do it now.”
You don’t book a flight or wait for the on-site engineer — you remotely log in to the USA router from the Mumbai Office.
This ability to manage a device anywhere in the world without physically touching it is called Remote Access.
What Are the Ways to Take Remote Access in Networking?
There are two common ways to remotely control a router or switch:
- Telnet — Unsecure Remote Access
- SSH (Secure Shell) — Secure Remote Access
What is Telnet?
Telnet is an older protocol used to access network devices remotely. It works, but has a major security issue:
Telnet sends everything as plain text.
- Username → Visible
- Password → Visible
- Commands → Visible
Anyone who captures network packets can read this information.
Summary: Telnet = Remote Access + Plain Text (No Encryption)
What is SSH (Secure Shell)?
SSH (Secure Shell) is a modern protocol for secure remote access. Unlike Telnet, SSH encrypts the whole session.
✔ SSH encrypts your username, password, and commands.
- Username → Encrypted
- Password → Encrypted
- Commands → Encrypted
Even if packets are captured, the attacker cannot understand the contents.
Summary: SSH = Remote Access + Encryption + Security
Telnet vs SSH — Quick Comparison
|
|---|
Real-life example:
You are working at a company, in the Mumbai office, and need to log in to a branch-office router in Pune.
If you use Telnet, anyone inside the office network or even someone who has tapped the network cable can capture packets and clearly see:
-
Your username
-
Your password
-
Every command you type
Because Telnet sends everything in plain text.
But if you use SSH, the entire session is encrypted, so even if someone tries to capture your packets, they see only scrambled data.
They cannot read your login credentials or commands.
Quick migration checklist: Telnet → SSH
- Check if the Device supports SSH.
- Update the device firmware if SSH is unavailable.
- Configure SSH on the router or switch.
- Disable Telnet access (recommended).
- Test SSH connectivity and remove Telnet access.
FAQs
What is the main difference between Telnet and SSH?
Answer: SSH encrypts the packet; Telnet does not encrypt the packet.
Which port does SSH use?
Answer: The Default SSH port is TCP 22
Which port does Telnet use?
Answer: The Default Telnet port is TCP 23
Is Telnet still used?
Answer: Rarely - Not Recommended
Conclusion
Both Telnet and SSH provide remote access to devices. Telnet is insecure because it sends data in plain text.
SSH is secure, encrypted, and feature-rich — and is the recommended choice for production environments.
Want hands-on guidance? Learn with Attari Classes
Master SSH, remote access best practices, and more with practical labs and friendly trainers.
Attari Classes — Practical Networking & Cloud Course
- Hands-on labs and real-world scenarios
- Experienced trainers who explain simply
- LMS access with recorded lessons
+91
7738375431