Meaning of line vty 0 4 in configuration of Cisco Router or Switch - IP With Ease (2024)

FAQs

Meaning of line vty 0 4 in configuration of Cisco Router or Switch - IP With Ease? ›

The abstract “0 – 4” means that the device can allow 5 simultaneous virtual connections which may be Telnet or SSH. In a way, we may say that 5 (0 – 4) are connection ports to the Router or Switch. In fact, we may have connection ports up to 16 (0 – 15).

The virtual terminal or “VTY” lines are virtual lines that allow connecting to the device using telnet or Secure Shell (SSH). Cisco devices can have up to 16 VTY lines. You can determine how many VTY lines you have by issuing “line vty 0 ?” from global configuration mode.

Configure the virtual terminal (vty) lines for the switch to allow Telnet access. If you do not configure a vty password, you will not be able to Telnet to the switch.

Lines 0 15 is vty lines 0, 1, 2 ,3 ,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15. for example if you were type in global configuration mode, line vty 0 15 you will enter configuration for lines 0-15. I hope this answers your question. Like Reply 2 likes.

By default all routers have 5 vty lines (factory defaults). Unless you configure the remaining available lines, there is no need for them to be protected.

VTY is a virtual port and used to get Telnet or SSH access to the device. VTY is solely used for inbound connections to the device. These connections are all virtual with no hardware associated with them. The abstract “0 – 4” means that the device can allow 5 simultaneous virtual connections which may be Telnet or SSH.

Using a standard ACL to secure VTY lines

To secure VTY lines, create a standard ACL that only permits the IP addresses you want to allow and apply this ACL to the VTY lines that you want to protect. Once the ACL is applied, the router will permit only the allowed IP addresses to access the VTY lines.

VTY lines are usually used for creating out-of-band management sessions to devices. If a password is not supplied on a vty line, that line cannot be used for managing the device. In some cases administrators may decide to let junior staff to use lines 0 - 4 and senior staff to use lines 5 - 15.

A VTY line is used for SSH and Telnet access to the device. Here you configure login parameters and password. A VLAN interface is in simplest terms the Layer 3 interface for a VLAN, allowing you to configure an IP address on it.

(Virtual TeletYpe) A command line interface created in a router for a Telnet session. The router is able to generate a VTY dynamically. See virtual terminal.

What is the default Vty timeout? ›

By default, an IOS device will disconnect a console or VTY user after 10 minutes of inactivity.

console 0 is the physical console port on the switch/router you plug into. line vty is when you remote into the switch/router via telnet or ssh. the config-line is letting you know you are currently in configuration mode for that specific line. Some commands are also different in relation to them.

Creating a VLAN

A switch supports a maximum of 4096 VLANs, among which VLANs 0 and 4095 are reserved for system use, and VLAN 1 is the default VLAN.

Typically up to 4094 VLANs. That actually depends on the device model. Theoretically, you could create all VLANs, but some devices have a limit, e.g. 250 VLANs, even though your VLAN numbers can be any valid VLAN number.

On a Cat 2900XL or Cat 2950 switch, there are 16 vty lines defined by default, in two groups, 0-4 and 5-15. These cannot be deleted, and you cannot add to the range.

(Virtual TeletYpe) A command line interface created in a router for a Telnet session. The router is able to generate a VTY dynamically. See virtual terminal.

console 0 is the physical console port on the switch/router you plug into. line vty is when you remote into the switch/router via telnet or ssh. the config-line is letting you know you are currently in configuration mode for that specific line. Some commands are also different in relation to them.

A VTY line is used for SSH and Telnet access to the device. Here you configure login parameters and password. A VLAN interface is in simplest terms the Layer 3 interface for a VLAN, allowing you to configure an IP address on it.