08/06/2026
Cisco Router Basic Commands.
Configuring hostname
Router #
Router terminal
Router(config) R1
R1(config)
R1 #
Enabling telnet and configuring telnet password
R1 #
R1 terminal
R1(config) vty 0 4
R1(config-line) zframez
R1(config-line)
R1(config-line)
R1(config)
R1 #
What is “vty” stands for ?
vty stands for “Virtual teleTYpe” or “Virtual teleTYpwriter”
The command line interface (CLI) used by devices like routers,switches or even computers are called as VTY. This name comes from the term TTY or TeleTYpewriter (a device with monitor and keyboard) which was used in the early days to give inputs and get output from a central computing system. TTY is also known as Terminal. Users need to use Telnet or SSH to access the CLI orVTY of a device.
Now since we are not using a physical TTY anymore, the term Vitrual teleTYpe or VTY is used to represent the CLI of devices.
What is 0 and 4 in the command “line vty 0 4” stands for ?
Each Telnet or SSH connection is called as a line connected to the device , and “line 0 4” means 5 telnet connections (line 0 , line 1 …. line4) are allowed to the device
The maximum number of simultaneous telnet connections allowed to a cisco device varies from model to model (5 and 16 are commonly used)
Configuring enable password
R1 terminal
R1(config) password zframez
R1(config)
Note: Users are allowed to telnet to a router only after configuring telnet and enable password
SHOW commands
R1 ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.1.1 YES manual up up
FastEthernet0/1 Unassigned YES unset down down
Router ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.1.0/24 is directly connected, FastEthernet0/0
R1 cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater
Device ID Local Intrfce Holdtme Capability Platform Port ID
R2 Fas 0/0
R1 cdp neighbors detail
Device ID: R2
Entry address(es):
IP address: 192.168.1.2
Platform: Cisco 2691, Capabilities: Router Switch IGMP
Interface: FastEthernet0/0, Port ID (outgoing port): FastEthernet0/0
Holdtime : 150 sec
Version :
Cisco IOS Software, 2600 Software (C2691-ENTSERVICESK9-M), Version 12.4(13b), RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Tue 24-Apr-07 15:33 by prod_rel_team
advertisement version: 2
VTP Management Domain: ''
Duplex: half
R1 ip protocols
Routing Protocol is "rip"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Sending updates every 30 seconds, next due in 0 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Redistributing: rip
Default version control: send version 1, receive any version
Interface Send Recv Triggered RIP Key-chain
FastEthernet0/0 1 1 2
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
192.168.1.0
Routing Information Sources:
Gateway Distance Last Update
Distance: (default is 120)
Checking configuration files
The current configuration is stored in a file “running-config” and the saved configuration which is loaded while router is booting is stored in the file “startup-config”
R1 running-config
R1 startup-config
To save the current configuration, you can use any one of the following commands
R1 running-config startup-config
R1 run start
R1
Configuring IP address and Mask in an interface
Following commands are used to configure IP and Mask in the interface “FastEthenet 0/0” of the router. “No Shutdown” command is used to enable the interface
R1 #
R1 terminal
R1(config) fastEthernet 0/0
R1(config-if) address 192.168.1.1 255.255.255.0
R1(config-if) shutdown
R1(config-if)
R1(config)
R1 #
Configuring static routes
R1 #
R1 terminal
R1(config) route 20.0.0.0 255.0.0.0 192.168.1.2
R1(config)
R1 #
The above "ip route" command is used to create a static route to the network 20.0.0.0/8 via the next-hop 192.168.1.2
R1 ip route
20.0.0.0/8 [1/0] via 192.168.1.2
C 192.168.1.0/24 is directly connected, FastEthernet0/0
R1 #
