Replace Telnet with SSH

NetLab lab Intermediate 4 tasks 20 points

R1 is managed over Telnet with a shared line password. Change that:

A local user admin with privilege 15 and the secret Adm1n!2026.
SSH version 2 with 2048-bit RSA keys (domain name example.com).
The vty lines take SSH only and log in with the local users.
Log in from ADMIN to prove it works.

How it works: this is VulnTech NetLab, a network simulator running in your browser. Click a device in the diagram to open its console and type commands, just like on real equipment (? shows help, Tab finishes a word). Click a cable to inspect it. Tasks tick themselves off as you complete them; questions are answered in the box under each task. Your work is kept if you reload; Reset starts the network over.

Solution explanation

SSH needs a hostname, a domain name and RSA keys; version 2 needs keys of at least 768 bits. login local replaces the shared line password with user names, and transport input ssh makes the router refuse Telnet on port 23.

Show solution

[R1]
enable
configure terminal
ip domain name example.com
crypto key generate rsa modulus 2048
ip ssh version 2
username admin privilege 15 secret Adm1n!2026
line vty 0 4
login local
transport input ssh
no password
end
[ADMIN]
telnet 10.1.1.1
ssh -l admin 10.1.1.1
Adm1n!2026
show users
exit