Telnet overview
Telnet (Telecommunication Network Protocol) is one of the earliest Internet applications. It is usually used in remote login applications to configure devices running remotely.
Telnet is a protocol of the APPLICATION application layer, which is an application based on the TCP protocol.
However, telnet is extremely lack of a secure authentication method. During the transmission process, it uses TCP for plain text transmission, which has hidden security risks. It is easy to incur malicious attacks such as host IP address spoofing and routing spoofing by simply providing telnet services, as is FTP. This traditional The method of transmitting passwords and data in clear text has slowly been rejected.
Configure Telnet login system topology
Use R1 to simulate the common user host, R2 to simulate the administrator host, and R3 as a device in the company's computer room.
R1
After configuring the interface IP, use Ping to test the device connectivity. In the aaa view, configure the local user name admin and cipher text password huawei, the user revision level is 3 (management level), configure the user access type as telnet, and VTY user view Next, change the authentication mode to aaa
interface g0 / 0/0
ip address 10.1.1.2
aaa
local-user admin password cipher huawei privilege level 3
local-user admin service-type telnet
user-interface vty 0 4
authentication-mode aaa
R2
interface g0/0/0
ip address 10.1.1.1
R3
interface g0/0/0
ip address 10.1.1.254 24
After the configuration is complete, the administrator connects to the router R3 through R2, and then enters the system view to configure.
Configuration only allows ordinary users R1telnet log, configure user1 user password privilege level in R3 is 1
aaa
local-user1 password the User Privilege Level 1 the cipher keyword 123456
local user1 the User-Service-of the type the Telnet
the User-interface vty 0 4
aaa
Refer to HCNA Routing Experiment Guide
