How to Configure a Cisco Router? The Simple Method

Network routers are the go-to for most people looking to get a high-speed internet connection. This is where Cisco comes in. With some of the best quality network routers that you can find in the market today. You can find Cisco routers in the homes and offices of people around the world.

No matter what the need might be of the customer, Cisco has something for everybody’s needs.  And in case, you have got yourself one of these fantastic network devices. Then, you might want to concoct a strong internet connection right away. Therefore, we are going to show you “how to configure a Cisco router?”

Once you follow the instructions and set your Cisco router up. Then, will you be able to enjoy the high-speed internet that you brought it for? But, as a matter of fact, we are going to cover some more details to help you perform this setup.

Reasons You Need to Know “How to Configure a Cisco Router?”

Before we go ahead and get into all the instructions you will need to configure your Cisco router. It is very important to know the reason why you might want to do this.

Cisco routers being some of the best routers that you can buy from the market. They are rather complicated devices, and in order to work, they need a lot of things working right. That is what makes a high-speed internet connection possible. Along with that, a lot of other features that are there.

In order to make that work properly, you have to know how to configure a Cisco router. And then, you will have to do it properly to make use of all those features.

But, there is another benefit that you are going to get if you do the setup properly. As we already mentioned that your Cisco router is a very complex device. So, because of that, many issues can develop in the system which will cause certain technical glitches in the future.

If you can properly configure your Cisco network router from the get-go. Then, you will be able to avoid a lot of those issues that might have come your way. This is going to save you a lot more time later on. Only if you just take a few minutes to configure the router properly.

How to Configure a Cisco Router in the Easiest Possible Manner?

After learning why you should carry out this setup process for your Cisco router. It is time to take a look at the technical part of the process.

So, here are the steps you need to configure a Cisco router.

Initiate a Terminal Emulation Program after Connecting the Router to the PC

You will have to connect your router to your computer and establish an active connection from there. It is going to be important for you to make that connection. As you are going to need for the setup process.

Use the Enable command to access the privileged EXEC mode, follow up with the erase command. Add the erase startup-config command after that to bring up a blank configuration.

After this, just restart your Cisco router with the reload command.

In case you get an IOS Prompt from the system, then make sure to click the No button for that. Now, that you have done this, it is time to take a look at the next step on this list.

Figure Out which ones are the Router’s Interfaces

Take a look at the Ethernet ports on the back side of the router. You will see that there are 4 ports for connecting LAN and 1 for connecting to the modem.

In case you do not see any label for that, just type the command show ip interface brief. It is going to be there in privileged EXEC mode.

After this, move on to the next step in the process.

Configure All of your IP Addresses

Here is where you are going to be starting the main part of the setup process. First, you will have to start the terminal configuration mode. To do that, type in the configure terminal command.

After that, type in the “no ip domain lookup” command and hit the Enter key after that. To stop the IOS from reading minor spelling mistakes as issues with the domain. Also, you will have to type in the no logging console command.

On the other hand, if you want to stop the IOS from making syslog message outputs to the console.

Now, it is time to set up the IP address for the interface of the LAN connection. Type in the “interface” command into that window and then enter interface BVI1 command.

After this, you will have to set the IP address from the interface and for that enter ip address.

From here, you will need to configure the WAN interface. So that, you can use DHCP to get to the IP address. Type in the commands interface FastEthernet4, then exit and finally, ip address dhcp, one after another.

Configure all the Access Lists

For this step, you will have to configure 2 different access lists. And these are going to be in the inbound direction.

It is because the traffic is going to come towards the device from your Cisco router. So, after you have set up the 2 access lists, move on to the next step.

Set the Basic TCP/UDP/ICMP Inspection Paths Up

The first thing you need to set up is the threshold for TCP SYN timeout. This is going to help counter the SYN flood DoS attacks.

For this, enter the ip tcp synwait-time 30 command. This makes the iOS forfeit any TCP session which does not happen within a span of 30 seconds.

After this, you will have to set the rules for ICMP, TCP and UDP individually. The commands that you are going to need are the following.

IP inspect name InspectRule icmp, ip inspect name InspectRule tcp and ip inspect name InspectRule udp.

Now, move on to the step after this.

Apply All of the Rules from the Previous Steps

After you have set up all the access lists and the TCP/UDP/ICMP inspection path rules. It is now time we apply them for the right interfaces going inbound.

First, open up the interface configuration mode with the interface FastEthernet4 command.

Now, in order to apply the access list, type in the command ip access-group 101 in. And after that, type in the ip inspect InspectRule in command to apply this inspection rule.

With that, we complete the first section of this step. And to get out of the interface configuration mode. Type in the command exit and you will be out of that.

After this, it is time to do similar for the LAN interface and here are the commands you need –

interface BVI1, ip access-group 100 in, ip inspect InspectRule in, and exit.

Thus, you have applied the rules in the inbound direction.

Configure the NAT

This step is a crucial one within the entire run. It is the NAT which translates into between the public internet and the internal network.

For this, it is important to set an access list which will only be for the NAT to use. Here are all the commands you will need for that –

IP access-list standard 10, permit, deny any, and exit.

Now, you will have to figure out which of the interfaces are going to take part in the NAT. To do that, enter the following commands in the order as you see it.

interface BVI1, ip nat inside, exit, interface FastEthernet4, ip nat outside, and exit.

Now after all these commands, it is time to put in the real NAT statement through the following command.

IP nat inside source list 10, interface FastEthernet4 overload.

Deactivate the STP and Activate Interfaces

For the penultimate step of the Cisco router configuration process. You are going to have to activate interfaces and deactivate the STP.

If you happen to have the Fast Ethernet type, then the commands for that will be –

interface FastEthernet4, no shutdown, and exit.

Keep in mind that you are going to have to do this for all the interfaces of your router. And that is going to activate all those router interfaces.

Now, for the other part of this step. You will have to deactivate the Spanning Tree Protocol, or in short the STP.

You will not have to do this if you will use your Cisco router in an office setting or similar. As for complex network layouts, this protocol can prove to be very useful.

Following are the commands that you are going to need to deactivate the STP.

interface FastEthernet0, spanning-tree portfast, and exit.

Put the New Configuration to Test

After all the steps for “how to configure a Cisco router?” that you have carried out by now. You have set up your Cisco router, but it is going to be very important to test the configuration out.

Type in the copy running-config startup-config command. This is going to save all the new settings that you have made in the nonvolatile memory. That way, after your Cisco router restarts, all these settings are going to be there.

After that, enter the show running-config command. This will display the details of the new configuration on the screen.


This completes all the necessary instructions if you want to know “how to configure a Cisco router?” After you have successfully carried out all the steps from this instructional. You are now ready to connect the Ethernet cable to the WAN port of your Cisco router.

And with that, you will be able to enjoy a high-speed internet connection. You can use it through either the wire connections from the LAN ports. Or you can go for the more common wireless Wifi medium.