Concept Guide

Modifying Global Parameters........................................................................................................................................816
Enabling SNMP Traps for Root Elections and Topology Changes..................................................................... 818
Modifying Interface Parameters................................................................................................................................... 818
Enabling SNMP Traps for Root Elections and Topology Changes........................................................................... 818
Inuencing RSTP Root Selection................................................................................................................................. 819
Conguring an EdgePort............................................................................................................................................... 819
Conguring Fast Hellos for Link State Detection...................................................................................................... 820
46 Software-Dened Networking (SDN).......................................................................................................821
47 Security................................................................................................................................................... 822
AAA Accounting.............................................................................................................................................................822
Conguration Task List for AAA Accounting........................................................................................................ 822
AAA Authentication....................................................................................................................................................... 824
Conguration Task List for AAA Authentication.................................................................................................. 825
Obscuring Passwords and Keys...................................................................................................................................828
AAA Authorization......................................................................................................................................................... 828
Privilege Levels Overview.......................................................................................................................................828
Conguration Task List for Privilege Levels..........................................................................................................829
RADIUS........................................................................................................................................................................... 833
RADIUS Authentication...........................................................................................................................................833
Conguration Task List for RADIUS...................................................................................................................... 834
Support for Change of Authorization and Disconnect Messages packets.......................................................837
TACACS+........................................................................................................................................................................848
Conguration Task List for TACACS+................................................................................................................... 848
TACACS+ Remote Authentication........................................................................................................................ 850
Command Authorization..........................................................................................................................................851
Protection from TCP Tiny and Overlapping Fragment Attacks............................................................................... 852
Enabling SCP and SSH................................................................................................................................................. 852
Using SCP with SSH to Copy a Software Image................................................................................................ 853
Removing the RSA Host Keys and Zeroizing Storage ....................................................................................... 854
Conguring When to Re-generate an SSH Key ..................................................................................................854
Conguring the SSH Server Key Exchange Algorithm....................................................................................... 854
Conguring the HMAC Algorithm for the SSH Server.......................................................................................855
Conguring the SSH Server Cipher List...............................................................................................................855
Conguring DNS in the SSH Server..................................................................................................................... 856
Secure Shell Authentication................................................................................................................................... 856
Troubleshooting SSH...............................................................................................................................................859
Telnet...............................................................................................................................................................................859
VTY Line and Access-Class Conguration................................................................................................................. 859
VTY Line Local Authentication and Authorization...............................................................................................860
VTY Line Remote Authentication and Authorization.......................................................................................... 860
VTY MAC-SA Filter Support................................................................................................................................... 861
Role-Based Access Control...........................................................................................................................................861
Overview of RBAC.................................................................................................................................................. 862
User Roles.................................................................................................................................................................864
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