Line vty 0 4

Transferred from

Http://hi.baidu.com/rxlly/blog/item/9072bc397ae18bde7c1e71f6.html

Line vty 0 4 does it mean to enable five Telnet sessions?
So does line vty 0 0 enable only one Telnet session?
On the 640-802 textbook, I saw line vty 0 1180. Suddenly it was so big that I couldn't figure it out.
Line console 0 indicates whether to enable the first Console port. Generally, the device has one control port. Is that true?

Best Answer
Vty is the virtual port for vro remote login. 0 4 indicates that five sessions can be opened at the same time. Line vty 0 4 indicates entering the vty port and configuring the vty port, for example, configuring the password, or ACL.
Entering vty 0 0 does not seem to have any practical significance. This is the first remote login to be enabled. Even if this restriction is imposed, it will log on from 1.
Line vty 0 1180 means that at the same time, 1181 terminals are allowed to log on remotely.
A common device is a Console port, that is, console 0.

Let's talk about vty first, virtual typle terminal. virtual terminal, I understand, is mainly used for telnet to vrouters and vswitches: User-vty 0 4 (a total of five virtual connections, the switch has 16 connections ), in fact, there are still Linux UNIX.

Common configuration principles:
Line is the command to enter the line mode, such as console, aux, vty, tty ...... All interfaces are in line mode and must be configured in line.

Vty is the virtual terminal port. When telnet is used, it is the peer vty port.

The vro has five vty ports: 0, 1, 2, 3, and 4. to configure these ports at the same time, line vty 0 4

Example Description: Creation and theoretical reasons ---------------------------------------------------------------------------------
Take a look at the following Configuration:
Line vty 0
Password 7 1010000812000e (123, suppose)
Login
Line vty 1 4
Password 7 0119070f5e12 .. sweat yourself ...)
Login

In this way, the first connection to the device is set to 123 as the password, the second connection is set to 321, and the second connection is set to 321 as the password ), because the first login will verify the configuration of vty 0, the second verification of vty 1, and so on ....
Bytes -----------------------------------------------------------------------------------------
Check this Configuration:

Line vty 0 4
Password 7 1010000812000e
Login
The password for this login device is always the same... (Summary vty 0 4 actually means 0-4... Khan ...)
Bytes -------------------------------------------------------------------------------------------
Also see:
Line vty 0
Password 7 1010000812000e
No Login
Line vty 1 4
Password 7 0119070f5e12
No Login
Line vty 5 15
Exec-timeout 0 0
Password 7 070520474b10
Login

After my test, because I use no login for all the 0-4 lines, the first level does not need to be verified during Telnet. When I use 0-4 lines, verify the password again.
1 vty 0 idle 00:00:09 192.168.1.150
2 vty 1 idle 00:01:28 192.168.1.150
3 vty 2 idle 00:04:13 192.168.1.150
4 vty 3 Idle 00:05:48 192.168.1.150
5 vty 4 idle 00:06:41 192.168.1.150
* 6 vty 5 idle 00:00:00 192.168.1.150

(Khan... I have completely tested the password. After 5 times, I started to verify the password)
Bytes -------------------------------------------------------------------------------------------------------
Bytes -------------------------------------------------------------------------------------------------------
The above is logon. If you do not want to log on, delete it.

Line vty 0
Password 7 1010000812000e
No Login
Line vty 1 4
Password 7 0119070f5e12
No Login
Line vty 5 15
Exec-timeout 0 0
Password 7 070520474b10
Login

As shown in the General No... test:
3550 (config) # No line vty 0
% Can't delete last 16 vty lines (in fact, vty is the port in iOS and cannot be deleted... Khan ..)
Bytes --------------------------------------------------------------------------------------------------------
Solution:
Want to delete vty (do not allow vty to log on)
Conf t
Line vty 0 4
Login
No Password
In this way, you will not be able to log on from vty, and the prompt will be "password not set", and then disconnect. (when you have no password to cancel the password, Telnet will reject the connection, so that Telnet will be disabled)