Although the configuration of speed and duplex is incredible easy, the concept behind them is somewhat important. Duplex defines how traffic will be sent and can be related to a 2-way radio vs. A telephone. With a 2-way radio, more so when there are more than 2 people on the same radio frequency, only 1 […]
In order to control what machines are plugged into your network, Cisco introduced the “switchport port-security” command. In this tutorial I’m going to explain how to use this command, and different options available using it. Below is the breakdown of the commands I used in the live demo, and an explanation of each. AOIP.ORG_Switch# terminal […]
The configuration of an IP address and default-gateway on a switch is slightly different from a router. Firstly a router doesn’t have a default-gateway but rather a default route. A switch on the other hand can have a default-gateway, especially if the device is in layer 2 mode. If the switch is a multi-layer switch […]
In the event that you have lost the configuration on your Cisco device, restoration is straight forward assuming of course you had made a backup. There are 2 ways to restore the configuration to put our device back to normal Copy and paste the backup configuration directly to the device Copy the configuration from a […]
Cisco brings out new versions of the operating system quite frequently, and of course there are different versions of the operating system for each of the appliances. Different IOS’s will support different commands and different features and it’s not uncommon to have to change the IOS that your device is running to support commands you […]
The first and most important rule in IT, is “Backup soon, Backup often!” It’s a logical statement but sadly one that many people only truly appreciate when it’s too late! Two of the most important files on a Cisco router are the Running-Configuration which stores the current configuration of your router, and the IOS (The […]
Two commands which are often confused or misunderstood, are the clock rate and bandwidth commands. In order to understand clock rate we first need to understand how the cabling works on routers. When connecting two routers together with a serial cable, one of the routers needs to host the DCE (Data Communications Equipment) side of […]
RIP (Routing Information Protocol) was one of the first routing protocols that hit the market, and still one of the easiest to configure. RIPv1 is a classfull routing protocol and does not support VLSM’s or CIDR values and sends it’s updates as a broadcast message with a destination address of 255.255.255.255 RIPv2 supports […]
A routing protocol is a method that routers use to share information with each other about networks they are connected to. We have seen in previous posts on this website (Creating a Static Route and Default Gateway of Last Resort) how we make routes ourselves and how to teach a router how to send packets […]
A router by default only knows about networks that are directly connected to it. If a router is not directly connected to the final destination subnet, then the router needs to learn, or be told how to get to that destination. Learning routes can take place through the use of routing protocols, however in […]
One of the first steps in troubleshooting a network, is to identify if the lines (links) are operational. On a Cisco router, the quickest way to see all lines as well as their status is by using the “show ip interface brief” command. In the live demo below, you will see that I have […]
In order to set up an IP address on an interface, we need to be in the interface level of the command line. This is a level within the global configuration level. From global configuration mode, we can enter the ‘interface serial 1/0’ command. If you are unsure of what interfaces are on the router, […]