Configuring DHCP relay in Cisco IOS

January 27th, 2012 No comments

There are times when you don’t want to use the routers built in DHCP server and want to use say a Windows Server to hand out your networks DHCP scopes. This guide is for basic DHCP relay configuration in Cisco IOS.

In this example we are going to be configuring the “ip helper” command on interface FastEthernet0/1. Our IP for the interface will be 10.10.20.1/24 and the IP of our DHCP server will be 10.10.10.5/24.

After you have accessed the command line of the router the first thing you will need to do is get into configuration mode by issuing the following command:

conf t

 

The DHCP server and relay agent should be enabled by default, however if for some reason they are not already enabled they can be enabled by issuing the following command:

service dhcp

 

Next we will want to enable the DHCP relay agent information option:

ip dhcp relay information option

 

Now we need to configure the actual interface via the following commands:

interface fastethernet0/1
ip address 10.10.20.1 255.255.255.0
ip helper-address 10.10.10.5
no shut

 

We now have a working DHCP relay pointing to our Windows DHCP Server for clients that connect to interface FastEthernet0/1. There are tons more ways to utilize and configure this functionality. For example you could assign “ip helper” to sub-interfaces for vlans. We will dive into the more advanced functionality in later articles, but for now this gives you the basic principal of the commands for configuring DHCP relay.

Categories: Cisco, Networking Tags:

How to Reset TCP/IP stack in Windows

January 14th, 2012 No comments

I have received a lot of questions lately about resetting the TCP/IP stack in Windows 7. The command is actually the same as it was in Windows XP. Just open a command line window and type the following:

netsh int ip reset resetlog.txt

You will then need to reboot to make sure the changes take effect.

Categories: Microsoft, Networking Tags:

Intro to VLAN Configuration

June 26th, 2011 No comments

Intro to Basic VLAN Configuration

This guide is more of a tutorial on basic VLAN configuration than an explanation of what VLAN’s are. If you don’t know what a VLAN is you probably won’t be reading this site to begin with. This guide also is not a “HOWTO” on configuring VLAN’s on a specific piece of equipment. We will be discussing the general basics of how VLAN’s are configured in theory. The goal is that after reading this guide you should be able to take the information learned and apply it to real world situations regardless of which brand/model VLAN switch you use.

In this guide I will be using an example network configuration with a 24 port switch with 5 VLAN’s (default, management, data, voice, and wifi), 1 server, 2 network printers, 10 computers, wireless AP, and an IP phone system with 8 IP phones. I will not be discussing configuring routers, wireless AP’s, or phone systems. These subjects will be covered in other more advanced articles in the future where we will build on the basics discussed here.

Read more…

Categories: Networking Tags:

List of Online Router Emulators

June 25th, 2011 No comments

This is a list of online router emulators for popular brands. Great for remote support situations. Will add to the list as I find more.

Note: Some of the links above even include a few switch emulators.

Categories: Networking Tags: , ,

OCC Reviews OCZ Vertex 3 240GB

June 23rd, 2011 No comments

OCC (Overclockersclub.com) recently posted a new review of the new OCZ Vertex 3 240GB SSD. It is an excellent review that is worth a few minutes of your time. As the review author ccokeman points out the only real con of this drive is the cost at a staggering $559. I love high performance as much as the next guy but at that price per GB is the performance increase really worth it?

Read the review here

Categories: Hardware Tags:

Android powered Panasonic Toughbook coming soon

June 18th, 2011 No comments

Panasonic has announced that they are releasing a 10″ Android powered Toughbook late this year. Details such as hardware specifics and price have not yet been released.

Categories: Hardware Tags:

Article on solid-state drives

June 18th, 2011 No comments

Ran across a good article on cnet about solid-state drives. The writer covers mainly the idea of longevity and reliability of solid-state drive technology.

Storage talk: Understanding your solid-state drive

Categories: Hardware Tags:

Pentagon to use simulator to practice cyberwar

June 18th, 2011 No comments

Now I know this makes me sound like a nerd but when I first read this headline the first thought through my head was the movie “War Games”. Regardless of how it turns out the Pentagon is creating an internet simulator to simulate cyber warfare and assess the results.

[Pentagon to simulate cyberwar - networkworld.com]

Categories: Networking, Security Tags:

How to add/edit OEM information in Windows 7

June 16th, 2011 No comments

How to add/edit OEM information in Windows 7

Whether you are a computer tech selling custom built computers or an IT administrator for a large corporation there are going to be times when it nice to be able to modify the OEM information for a computer in Windows. If you are building a computer for a customer it is nice to have your information for contact purposes. If you are adding a computer to a large corporate network you may want to edit the OEM information for simpler network management. Regardless of your reasons doing this task is much different than in previous versions of windows. In this article I will show you how to accomplish this in Windows 7.

Read more…

Categories: Microsoft Tags:

iPad to be sold at Target

September 25th, 2010 No comments

Starting October 3rd the iPad from Apple will be available for sale at Target retail stores. This is good news for those that have a Target store credit card as they will be able to purchase an iPad at a 5% discount using their card.

Categories: Apple Tags: , ,