📖 What is Port Security?
A Layer 2 security feature on switches that restricts interface access by limiting the number of valid MAC addresses allowed to send traffic into the port.
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Sensei Says:
"The default violation mode is 'shutdown'. The interface goes into an err-disabled state and requires a shut/no shut sequence (or errdisable recovery) to bring back up!"
📚 Certification: Certified Network Associate (200-301)
🔑 What are the Key Concepts of Port Security?
- ▸ Layer 2 security feature
- ▸ Limits valid MAC addresses on a port
- ▸ Violation modes: Protect, Restrict, Shutdown
🎯 How does Port Security appear on the 200-301 Exam?
Diagnosing an err-disabled port caused by a port security violation.
Configuring sticky MAC addresses to dynamically learn and save secure MAC addresses.
❓ Frequently Asked Questions
What is the default violation mode for Port Security?
The default mode is 'shutdown', which puts the port in an err-disabled state.
How do you recover a port from an err-disabled state?
You can either manually issue a 'shutdown' followed by 'no shutdown' command on the interface, or configure errdisable recovery.
Related Terms from Certified Network Associate
DHCP Snooping
EtherChannel
WPA2 (Wi-Fi Protected Access 2)
Administrative Distance (AD)
REST (Representational State Transfer)
Subnet Mask