You learn a lesson with telnet protocol

telnet protocol

If the corporate network has one or more network devices need to be configured and managed remotely, administrators can use Telnet to connect to each piece of equipment, these network equipment for centralized management and maintenance

Telnet application scenarios

Telnet terminal can be centrally managed by the local and remote network devices
Telnet runs a client / server model. Telnet protocol based on TCP, the default server port number is 23, Telnet server to establish the connection with the client through the port

Authentication Mode

Telnet configuration

telnet server configuration

[Huawei]interface Ethernet 2/0/0    
[Huawei-Ethernet2/0/0]ip address 10.1.1.1 24
[Huawei]user-interface vty 0 4
[Huawei-ui-vty0-4]authentication-mode password  
[Huawei-ui-vty0-4]set authentication password cipher
 Enter Password(<8-128>): huawei12

telnet client to connect

<Host>telnet 10.1.1.1
Trying 10.1.1.1 ...
Press CTRL+K to abort
Connected to 10.1.1.1 ...
Login authentication
Password:
Info: The max number of VTY users is 10, and the number
      of current VTY users on line is 1.
      The current login time is 2013-04-19 16:32:00.
<Huawei>

LAN machines can not access how to solve?

With windows client, for example:
1, a single machine can not access someone else can be
a, ping www.baidu.com if the pass but still can not access the browser, then the problem may be poisoning
b, ping 10.0.0.254 gateway purpose is to exclude the physical chain route (cable network card driver IP settings, etc.)
under if the gateway not ping ping other IP address and its own IP address if the ping fails, then your IP settings NIC driver physical link under examination LAN If the ping succeeds, then the gateway will not let you networking the (made policy limits)
c, if the gateway can ping ping in the public network IP address (remember that a few public IP address) as ping 203.81.19.1 If the ping, then look at the DNS configuration
d see DNS method host / diag / nslookup check DNS
E, equipment problems routing if the DNS configuration is no problem to see behind the gateway, and issues to the ISP line
2, not on the network over a wide area
router ISP core switches virus ARP spoofing gateway gateway address is occupied local DNS problems with
the core switches switch bad loop