Cisco router provides greater facility than other routers and facilitates better connection to a network. Unless you know how to set up a Cisco router, your device cannot access the internet. Therefore, let us discuss the steps by which you can set up a Cisco router as quickly as possible.
Prerequisites for setting up a Cisco router
If you want to set up the router for your home or for official usage, then buy a router which belongs to these model numbers- 806, 836, 851, or 871. Besides this, the router should have at least two ethernet interfaces. It’s better to have a router with the latest version. You will need a Cisco console cable and a computer with a terminal emulation program. Now follow the steps given below:
Use a console cable to connect the Cisco router to a PC. Type ‘cmd’ in the search field of the computer to run the Command Prompt. Then type ‘enable’ command in it and press ‘Enter’ to get into the ‘Privileged EXEC’ mode. Type ‘ erase startup-config’ in the Command line and press ‘Enter’ and you will get a blank configuration. If your computer displays an IOS prompt, then simply ignore it.
Check that which ethernet port on your router is for WAN devices and which one is for LAN connection. If the ethernet ports are not labeled, then go to ‘Privileged EXEC’ mode and type the command, ‘show IP interface brief.’
Remain in the ‘Privileged EXEC’ mode and type ‘configure terminal’ in the command line. Type ‘no IP domain lookup’ after the router has entered the terminal configuration mode and press ‘Enter.’ You can thereby, prevent the IOS from making any spelling mistakes you make into domain names. Moreover, enter the command, ‘no logging console’ to prevent IOS from generating unwanted messages when you are at work. Set up the IP address for the LAN interface. After that type ‘interface FastEthernet4’ and then ‘IP address DHCP’ and hit ‘Enter.’ Type ‘Exit’ command to get out of the configuration mode.
Here you will need to set up an inbound and an outbound access list. You will need to apply the access list 100 to the LAN interface and 101 to the WAN interface. The first line of the access list is to enter the Cisco router in the access list configuration mode. Use a cable modem so that the DGCP traffic can enter the WAN interface. The third and fourth lines let the TCP or UDP traffic to enter the WAN interface. The task of the fifth, sixth and seventh lines is to ensure that the Internet Control Message Protocol enter the WAN interface. Note that, you will require three lines in the access list to use ping and traceroute for troubleshooting.
Type ‘IP TCP synwait-time 30’ to command IOS to drop ant TCP session which is not established within this 30 seconds. Follow the on-screen prompts to set up an inspection rule separately for TCP, UDP, and ICMP.
For WAN interface, type ‘interface FastEthernet4’ in the Command Prompt to enter the interface configuration mode. Then type ‘IP access group 101 in’ to apply the access list. After that, enter ‘IP address InspectRule in’ to apply the inspection rule. Exit the interface configuration mode and follow the same process to apply access lists and inspection rules for the LAN interface.
The purpose of NAT is to translate addresses between the internal network and the public internet. Enter the following commands one after another:
IP access list standard 10
Make sure that the configuration mode has a standard and not an extended access list as it will help the router to permit and deny traffic to and from specified IP addresses and networks. But unlike an extended access list, the standard access list does not let you specify the destination or the type of traffic. Now the second command mentioned above will allow you to identify the traffic you would like to translate. It will also translate the traffic on the internal LAN for the internet. The third command will prevent the router from translating other traffic. The fourth command will take your router out of the configuration mode. Type ‘IP nat inside source list 10 interface FastEthernet4 overload’ command to share one public address among several internal private addresses.
Type ‘interface FastEthernet4 no shutdown exit’ to test the configuration of your Cisco router. Repeat this process for every physical interface on your computer. Unplug the console cable and use an ethernet cable to connect the PC to a LAN port. Open a Telnet connection to the IP address of the router and access the router. If your router permits, then disable Spanning Tree Protocol(STP) on the internal LAN interface. Remember not to disable STP if you want to set up a complex network of switches on your network. But, if your network is small, then disable STP to facilitate internal LAN devices connecting faster to your router.
Enter ‘copy running-config startup-config’ to save all the settings to non-volatile memory on your computer. Type ‘show running-config’ command to get a copy of the configuration you have created on your computer’s screen. If you wish, you can use the text editor to edit the configuration to change the settings of your router. Then connect the ethernet cable to the router’s WAN port and try to access the internet. Now you have finally set up your Cisco router.
If you have gone through the article carefully, then you won’t encounter any more issues to set up a Cisco router.