ios

Cisco IOS How-To Tips and Tricks

I have published over 20 different Cisco IOS tip and trick articles over at the Petri IT Knowledgebase. In these Cisco tips, I cover things like setting up a Cisco switch, VLAN configuration, DDNS, ACLs, and selecting the right router for your CCNA studies.

Of these 20+ Cisco tips, here are 5 of the most popular:

• Cellular Data to your Cisco Router
• Cisco 800 series Routers - the best routers to practice for your CCNA exam and learn the IOS
• Configuring Dynamic DNS (DDNS) in the Cisco IOS
• How to Recover a Lost Password on a Cisco Switch
• How to Setup VLAN Trunking Protocol (VTP) on Cisco Switches

I hope you will check them out!

Video: How to perform DHCP Snooping from Train Signal

In this sample of the Train Signal Cisco CCNA training course, Chris Bryant offers a demonstration on how to perform DHCP snooping in the Cisco IOS.

Cisco administration 101: Five interface commands you should know

Configuring Cisco routers isn’t hard if you don’t know how to use interface commands. Let’s face it, you have to know commands like no shutdown, ip address, description, bandwidth, and access-group.

In my new article, I discuss all of these commands in detail with configuration examples. Read the full article at: Cisco administration 101: Five interface commands you should know

Take advantage of the Cisco License Manager to keep you organized

Software license compliance is critical in IT Departments today. After all, you don’t want your company to get into legal trouble over mismanagement of licenses, do you? To help you out, Cisco has something to make your life easier.

Did you know that Cisco offers a free device inventory, license inventory, and license/feature deployment software application? Registered Cisco users can download this application for free from Cisco.

Read all about it, learn how it can help you, and where you can download the free Cisco License Manager at my article: Take advantage of the Cisco License Manager to keep you organized

What is CDP and how can it help you?

he Cisco Discovery Protocol (CDP) is a proprietary layer 2 management protocol for networks. CDP provides network device inventory, connectivity information, and IP next hop info. It works on LANs and WANs. CDP also works no matter the layer 3 network in use. This, no matter if you are running TCP/IP, Decnet, or Novell IPX- CDP will still function and provide the same info. CDP is excellent for troubleshooting.

I have used CDP to find out what the IP address is of a misconfigured router or switch on the other side of a WAN link. CDP can be enabled/disabled at the interfae level or globally on the whole router/switch.

Here are 6 CDP commands you should know:

1. cdp run and cdp no run - to enable and disable CDP globally
2. cdp enable and no cdp enable - to enable and disable cdp per interface
3. show cdp neighbors - to view see what routers and switches are connected to you on the LAN or WAN.
4. show cdp interfaces - to see which of your interfaces are participating in the CDP exchange
5. show cdp entry - to look at a particular switch or router that is a neighbor
6. show traffic - to see statistics about how many CDP packets have been exchanged

Also, you can also set cdp timers and clear cdp statistics.

For more information on CDP see the Cisco IOS Configuration Fundamentals Configuration Guide, Configuring Cisco Discovery Protocol (CDP) section.

Ensure Cisco router redundancy with HSRP

Cisco routers are very reliable but no router is perfect. Routers can go down at anytime due to bad hardware, failed IOS upgrades, or just plain human errror.

Your default gateway router is your connection to the outside world (that’s the Internet). I recommend you configure the hot standby router protocol (HSRP) on your Cisco roger functioning as your default gateway (perhaps other core routers too).

To learn all about HSRP and how to configure it, read my article: Ensure Cisco router redundancy with HSRP

Synchronize a Cisco router’s clock with Network Time Protocol (NTP)

Is the time and date on your cisco router I switch correct? Both time and date need to be accurate for things like security logs, troubleshooting logs, time based ACLs, and a variety of other reasons.

Fortunately, the network time protocol, or NTP, was created to sync the time and date on our cisco routers down to the microsecond.

NTP isn’t hard to configure with the help of my step by step article:
Synchronize a Cisco router’s clock with Network Time Protocol (NTP)

The 10 Cisco IOS Router file management commands you must know

In my latest article, I cover the top 10 Cisco IOS router file management commands that every Network Admin should know. These, of course, start with dir, and cd, fsck, verify, and many more - all commands that you might not have known you could do on your Cisco router.

This has been one of my most popular articles with 26 votes and 11 comments so far. Read the full article at: The 10 Cisco IOS Router file management commands you must know