Purpose
Command or Action
switch(config)#
show login on-failure log
Displays whether the switch is configured to log successful
authentication messages to the syslog server.
(Optional)
show login on-successful log
Example:
Step 5
switch(config)#
show login on-successful log
Copies the running configuration to the startup
configuration.
(Optional)
copy running-config startup-config
Example:
Step 6
switch(config)#
copy running-config startup-config
Enabling CHAP Authentication
The Cisco NX-OS software supports the Challenge Handshake Authentication Protocol (CHAP), a
challenge-response authentication protocol that uses the industry-standard Message Digest (MD5) hashing
scheme to encrypt responses. You can use CHAP for user logins to a Cisco NX-OS device through a remote
authentication server (RADIUS or ).
By default, the Cisco NX-OS device uses Password Authentication Protocol (PAP) authentication between
the Cisco NX-OS device and the remote server. If you enable CHAP, you need to configure your RADIUS
or server to recognize the CHAP vendor-specific attributes (VSAs).
Cisco Nexus 9K Series switches support the CLI command, aaa authentication login ascii-authentication, only
for , but not for RADIUS. Ensure that you have disabled aaa authentication login ascii-authentication
switch so that the default authentication, PAP, is enabled. Otherwise, you will see syslog errors. For example:
2017 Jun 14 16:14:15 N9K-1 %RADIUS-2-RADIUS_NO_AUTHEN_INFO: ASCII authentication not supported
2017 Jun 14 16:14:16 N9K-1 %AUTHPRIV-3-SYSTEM_MSG: pam_aaa:Authentication failed from
192.168.12.34 - dcos_sshd[16804]
Note
This table shows the RADIUS and VSAs required for CHAP.
Table 5: CHAP RADIUS and VSAs
Description
VSA
Vendor-Type
Number
Vendor-ID
Number
Contains the challenge sent by an AAA server to a
CHAP user. It can be used in both Access-Request
and Access-Challenge packets.
CHAP-Challenge
11
311
Contains the response value provided by a CHAP
user in response to the challenge. It is used only in
Access-Request packets.
CHAP-Response
11
211
Before you begin
Disable AAA ASCII authentication for logins.
Cisco Nexus 9000 Series NX-OS Security Configuration Guide, Release 9.x
23
Configuring AAA
Enabling CHAP Authentication