Debugging Telnet sessions: You Telnet into a remote Cisco device and run the command debug ip rip, but no debug output appears. What is the likely reason?

Introduction / Context:
In Cisco IOS, debug output by default goes to the console port. When connected through Telnet or SSH, you will not see debug messages unless you explicitly enable logging to the vty session.

Given Data / Assumptions:

• You Telnet into a remote router.
• You issue a debug command (e.g., debug ip rip).
• No debug output is displayed in your Telnet session.

Concept / Approach:
To view debug output remotely, you must run 'terminal monitor'. This command enables the display of log/debug messages on your VTY session. Without it, all debug output is still sent to the console only.

Step-by-Step Solution:

Verification / Alternative check:
Test by sending RIP updates (e.g., clear ip route *) and observe debug lines appear. Run 'terminal no monitor' to turn it off afterward.

Why Other Options Are Wrong:
show ip rip: A display command; not related. IP addressing incorrect: Would not suppress all debug output. Debug only console: True by default, but terminal monitor overrides this behavior.

Common Pitfalls:
Forgetting to disable debugs after use can overwhelm CPU and crash the router. Always use 'undebug all' or 'u all' when finished.

Final Answer:
You must use the terminal monitor command.