Users Guide

44 Rapid Spanning Tree Protocol (RSTP)..................................................................................................... 693
Protocol Overview.........................................................................................................................................................693
Conguring Rapid Spanning Tree................................................................................................................................ 693
Related Conguration Tasks...................................................................................................................................693
Important Points to Remember................................................................................................................................... 693
RSTP and VLT..........................................................................................................................................................694
Conguring Interfaces for Layer 2 Mode....................................................................................................................694
Enabling Rapid Spanning Tree Protocol Globally....................................................................................................... 695
Adding and Removing Interfaces................................................................................................................................. 697
Modifying Global Parameters....................................................................................................................................... 697
Enabling SNMP Traps for Root Elections and Topology Changes.................................................................... 699
Modifying Interface Parameters.................................................................................................................................. 699
Enabling SNMP Traps for Root Elections and Topology Changes.......................................................................... 699
Inuencing RSTP Root Selection.................................................................................................................................699
Conguring an EdgePort.............................................................................................................................................. 700
Conguring Fast Hellos for Link State Detection....................................................................................................... 701
45 Software-Dened Networking (SDN)...................................................................................................... 702
46 Security................................................................................................................................................... 703
AAA Accounting.............................................................................................................................................................703
Conguration Task List for AAA Accounting........................................................................................................ 703
AAA Authentication....................................................................................................................................................... 705
Conguration Task List for AAA Authentication.................................................................................................. 706
Obscuring Passwords and Keys...................................................................................................................................709
AAA Authorization......................................................................................................................................................... 709
Privilege Levels Overview....................................................................................................................................... 709
Conguration Task List for Privilege Levels...........................................................................................................710
RADIUS............................................................................................................................................................................ 714
RADIUS Authentication............................................................................................................................................714
Conguration Task List for RADIUS....................................................................................................................... 715
TACACS+.........................................................................................................................................................................719
Conguration Task List for TACACS+....................................................................................................................719
TACACS+ Remote Authentication.........................................................................................................................720
Command Authorization..........................................................................................................................................721
Protection from TCP Tiny and Overlapping Fragment Attacks............................................................................... 722
Enabling SCP and SSH..................................................................................................................................................722
Using SCP with SSH to Copy a Software Image.................................................................................................723
Removing the RSA Host Keys and Zeroizing Storage ........................................................................................724
Conguring When to Re-generate an SSH Key ..................................................................................................724
Conguring the SSH Server Key Exchange Algorithm....................................................................................... 724
Conguring the HMAC Algorithm for the SSH Server....................................................................................... 725
Conguring the SSH Server Cipher List............................................................................................................... 726
Secure Shell Authentication....................................................................................................................................726
Troubleshooting SSH............................................................................................................................................... 729
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