Concept Guide

Important Points to Remember....................................................................................................................................783
RSTP and VLT.......................................................................................................................................................... 784
Conguring Interfaces for Layer 2 Mode....................................................................................................................784
Enabling Rapid Spanning Tree Protocol Globally........................................................................................................785
Adding and Removing Interfaces................................................................................................................................. 787
Modifying Global Parameters........................................................................................................................................787
Enabling SNMP Traps for Root Elections and Topology Changes.....................................................................789
Modifying Interface Parameters...................................................................................................................................789
Enabling SNMP Traps for Root Elections and Topology Changes...........................................................................789
Inuencing RSTP Root Selection.................................................................................................................................789
Conguring an EdgePort.............................................................................................................................................. 790
Conguring Fast Hellos for Link State Detection....................................................................................................... 791
46 Software-Dened Networking (SDN)...................................................................................................... 792
47 Security................................................................................................................................................... 793
AAA Accounting.............................................................................................................................................................793
Conguration Task List for AAA Accounting........................................................................................................ 793
AAA Authentication....................................................................................................................................................... 795
Conguration Task List for AAA Authentication.................................................................................................. 796
Obscuring Passwords and Keys...................................................................................................................................799
AAA Authorization......................................................................................................................................................... 799
Privilege Levels Overview....................................................................................................................................... 799
Conguration Task List for Privilege Levels..........................................................................................................800
RADIUS...........................................................................................................................................................................804
RADIUS Authentication...........................................................................................................................................804
Conguration Task List for RADIUS...................................................................................................................... 805
TACACS+........................................................................................................................................................................809
Conguration Task List for TACACS+...................................................................................................................809
TACACS+ Remote Authentication......................................................................................................................... 810
Command Authorization...........................................................................................................................................811
Protection from TCP Tiny and Overlapping Fragment Attacks................................................................................812
Enabling SCP and SSH.................................................................................................................................................. 812
Using SCP with SSH to Copy a Software Image................................................................................................. 813
Removing the RSA Host Keys and Zeroizing Storage ........................................................................................ 814
Conguring When to Re-generate an SSH Key .................................................................................................. 814
Conguring the SSH Server Key Exchange Algorithm........................................................................................814
Conguring the HMAC Algorithm for the SSH Server........................................................................................815
Conguring the HMAC Algorithm for the SSH Client......................................................................................... 815
Conguring the SSH Server Cipher List................................................................................................................816
Conguring the SSH Client Cipher List................................................................................................................. 817
Secure Shell Authentication.................................................................................................................................... 817
Troubleshooting SSH................................................................................................................................................821
Telnet................................................................................................................................................................................821
VTY Line and Access-Class Conguration.................................................................................................................. 821
VTY Line Local Authentication and Authorization............................................................................................... 822
Contents
25