Users Guide

Security and
Access
Sysadmin
Command Mode EXEC
Usage
Information
This command uses the key-server name and key-id to install the key into the switch GPG key ring.
Use this command before you use the image verify or image secure-install commands with
the GPG option. If the key is not installed in the key ring, the image verify and image secure-
install commands fail when used with the GPG key.
Example
OS10# image gpg-key key-server pool.sks-keyservers.net key-id 47CB9029
Supported
Releases
10.5.1.0 or later
Switch management access
OS10 provides security to all management access through console, Telnet, SSH connections, and SNMP requests.
SSH server
In OS10, the secure shell server allows an SSH client to access an OS10 switch through a secure, encrypted connection. The
SSH server authenticates remote clients using RADIUS challenge/response, a trusted host file, locally-stored passwords, and
public keys.
Configure SSH server
● The SSH server is enabled by default. You can disable the SSH server using the no ip ssh server enable command.
● Challenge response authentication is disabled by default. To enable, use the ip ssh server challenge-response-
authentication command.
● Host-based authentication is disabled by default. To enable, use the ip ssh server hostbased-authentication
command.
● Password authentication is enabled by default. To disable, use the no ip ssh server password-authentication
command.
● Public key authentication is enabled by default. To disable, use the no ip ssh server pubkey-authentication
command.
● Password-less login is disabled by default. To enable, use the username sshkey or username sshkey filename
commands.
● Configure the list of cipher algorithms using the ip ssh server cipher cipher-list command.
● Configure key exchange algorithms using the ip ssh server kex key-exchange-algorithm command.
● Configure hash message authentication code (HMAC) algorithms using the ip ssh server mac hmac-algorithm
command.
● Configure the SSH server listening port using the ip ssh server port port-number command.
● Configure the SSH server to be reachable on the management VRF using the ip ssh server vrf command.
● Configure the SSH login timeout using the ip ssh server login-grace-time seconds command, from 0 to 300;
default 60. To reset the default SSH prompt timer, use the no ip ssh server login-grace-time command.
● Configure the maximum number of authentication attempts using the ip ssh server max-auth-tries number
command, from 0 to 10; default 6. To reset the default, use the no ip ssh server max-auth-tries command.
The max-auth-tries value includes all authentication attempts, including public-key and password. If you enable both,
public-key based authentication and password authentication, the public-key authentication is the default and is tried
first. If it fails, the number of max-auth-tries is reduced by one. In this case, if you configured ip ssh server
max-auth-tries 1, the password prompt does not display.
Regenerate public keys
When enabled, the SSH server generates public keys by default and uses them for client authentication:
● A Rivest, Shamir, and Adelman (RSA) key using 2048 bits.
● An Elliptic Curve Digital Signature Algorithm (ECDSA) key using 256 bits
● An Ed25519 key using 256 bits
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Security