Tech Grab Bag

Cat5E vs Cat6

2012-02-07T10:07:00.000-06:00

Here is a good video that addresses the differences between Cat5E and Cat6.

IPv6 Resource

2012-01-23T20:13:00.000-06:00

Here is a resource from Cisco for IPV6 research. It is full of videos, blog entries, and other related documents.

https://supportforums.cisco.com/community/netpro/network-infrastructure/ipv6-transition

Wireshare Capture Filter - subnet

2011-12-15T16:37:00.000-06:00

If you want to capture all data from a specific subnet there is an easy way to do this in Wireshark. Go into the capture filter screen, create a new filter, name it, and in the filter string space enter the network info using the following format.

net 192.168.1.0/24

Visio Stencils - Cisco

2011-12-08T09:05:00.001-06:00

Here is a link to Cisco's Visio stencils.

Visio Stencils

Ping scan with nmap

2011-11-28T13:21:00.001-06:00

At times you may just need to be able to find out what IP addresses are currently in use on your network. One quick way to do this is with nmap.

With Zenmap it's just a matter of selecting the "Ping scan" profile and entering a range in the target field, such as 192.168.1.1-254

If you are using nmap from the command line simply type the following, nmap -sP 192.168.1.1-254

View PAE setting on Windows Server 2008

2011-10-20T08:07:00.000-05:00

If you are running the 32-bit version of Windows Server 2008 and have more than 4GB of RAM in your server you may want to know if you are actually running PAE. To do so you can run the following from the Administrator Command Prompt.

"bcdedit /enum | find /I "pae"

It should return something like this if you have PAE enabled.

pae ForceEnable

Fedora 16

2011-10-18T10:11:00.002-05:00

Display running services on Windows

2011-07-27T21:17:00.000-05:00

You may already know that you can start and stop windows services using the
net start -service name-
net stop -service name-
commands, but what you might not know is how to simply display what services are currently running.

This is rather simple and straight forward, simply type the following.
net start

This should display all of the services currently running on your system. If you have a lot of services running and know the service name you are looking for you can use the following to see if it is running.
net start | find "-service name-"

Windows Server 2008 core - default login

2011-07-20T10:41:00.000-05:00

If you are new to installing Windows Server 2008 core you will notice there is a logon screen after the first reboot even though you hadn't previously setup a default password.

To get past this screen, enter administrator as the user name with no password. After that you will be prompted to change your password. Once you have set your new administrator password you are good to go.

Find Processes Running On A Remote System

2011-06-09T08:21:00.002-05:00

If you're working in a Windows environment and you have the rights to do so, you can find the process running on a remote machine by running the following command.

tasklist /s -machine name-

This will give you important info like the process name, PID, and memory usage.

Wireshark - DHCP filter

2011-05-31T13:21:00.001-05:00

If you ever need to capture just DHCP traffic while using Wireshark simply use the following capture filter string.

port 67 or port 68

Fedora 15 Countdown

2011-05-04T09:13:00.001-05:00

Scientific Linux - scp missing

2011-04-07T10:46:00.000-05:00

I ran across something interesting while working with Scientific Linux 6. I had done a minimal install and attempted to scp some files over to it from another box. This fails because the minimal install apparently does not install scp. If you ran into this as well, the fix is rather simple.

yum install openssh-clients

Windows 7 - MacBook Pro - right click

2011-03-16T16:18:00.000-05:00

If you've setup your MacBook Pro to dual boot with Windows 7 you might find it handy to be able to right click without attaching an external mouse. It feels a little un-natural at first but it's pretty straight forward.

Rest two fingers on the trackpad and click the mouse button.

That's all there is to it.

Disable IPv6 in Debian

2011-01-18T09:37:00.001-06:00

As I've posted before that there may be reasons you want to disable IPv6. A simple way to do this in Debian is to edit /etc/modprobe.d/aliases with the following lines

alias net-pf-10 off
alias ipv6 off

Restart and verify you are no longer running IPv6 by using the netstat command.

netstat -tunlp

Restarting interfaces in Solaris

2011-01-12T17:48:00.004-06:00

On occasion you may just want to bring an interface down and then backup up again without actually restarting the network services. To restart interfaces in Solaris simply do the following.

For the example we'll say and ifconfig -a showed you ce0, ce1, ce2, ce3

To bring an interface down: ifconfig ce0 down
To bring an interface up: ifconfig cd0 up

Fedora - public mirrors

2010-12-12T12:18:00.001-06:00

Looking for the Fedora public mirrors? I do really like the current Fedora project website. However, it isn't always easy to get to the list of public mirrors from the site since they redesigned it.

Fedora Public Mirrors

Sci Fi Science

2010-11-30T21:35:00.000-06:00

For those of you that haven't seen it, Sci Fi Science is a show on the Science Channel that looks at technology used in Sci Fi movies and tries to create them using current technology or technology currently in development. It is fascinating to learn about some of the technology being developed and how it might be combined with other tech to make the things we only dream of become reality.

Love this show, check it out.

Sci Fi Science

Data Encapsulation Terminology

2010-11-29T20:41:00.000-06:00

It is important to use the correct terminology when referring to the different levels of data encapsulation.

Segment - is the term used for the transport layer
Packet - is the term used for the network layer
Frame - is the term used for the network access layer

The reason I point this out is because I myself am guilty of sometimes just referring to everything as a packet. While most people are able to track with what you are saying, even though you may be using the wrong term, it isn't a good habit to get into. This is especially true if you find yourself troubleshooting complex network problems with vendors who need precise information when trying to work through a problem with you.

Always make a conscious effort to use the correct terms.

Fedora 14 - initial thoughts

2010-11-16T21:40:00.000-06:00

I finally got around to installing Fedora 14. On the surface it is really not much different than Fedora 13. Though I have to admit, the default wallpaper is really cool looking.

The install went the same as always, nothing new to speak of from the Fedora 13 installer.

Performance seems pretty good, I am running it on an old 1.60GHz Pentium4 that I dug out of the pile. It also only has 512MB of RAM, but as I said seems to be performing just fine with the default Gnome install.

With my initial look at Fedora 14 I would say it is pretty nice, haven't run into anything weird so far like I have with some previous versions of Fedora.

Spaces icon missing from dock

2010-10-29T11:07:00.000-05:00

If you have accidentally deleted or simply don't see the Spaces icon on the dock of your Mac don't worry, it's an easy fix.

Simply open the Applications folder, then open the Utilities folder, then drag the Spaces icon to your dock.

That is all there is to it.

Macs and anti-virus

2010-10-27T18:57:00.001-05:00

I know that Mac users like to run around commenting about how they don't have to worry about getting a virus, I have one too for the record, but that is not entirely true. SC Magazine reported today about the Koobface exploit and how a Mac variant is now in the wild and I would suspect as the Mac continues to gain popularity we may see more worms making their way over to the Mac side from the Windows world.

I coincidentally installed the Mac version of our corporate A/V solution onto the management server allowing me to now run the same managed A/V solution on my Mac as on my Windows computer. In my case, this didn't cost any extra for us to add Mac support, just a little of my time.

I would recommend checking to see if your anti-virus vendor offers a Mac client as part of the suite and if it's at no additional charge, as was my case, even better.

Zenoss - locations

2010-08-30T07:44:00.003-05:00

I've tried setting up and running Zenoss a couple times and the newest version 3.0.1 is pretty nice. Like previous versions it's easy to download, install and get up and running. Some of the options are in new places so it took me a little time to figure out where they were, but again the same ease of use was there.

One thing that was not so straight forward was how to get devices to show up in their locations. This isn't, as I thought, information that is pulled out of SNMP, but rather information that you define. As it turns out though, it is as simple as clicking just to the left of the device name and dragging it into the location you have defined. Once you have done that you will be able to manage your device both by device type that you defined at discovery as well as by location that you can customize as you like.

Cisco: connecting the old with the new

2010-08-24T19:25:00.003-05:00

I spend as much time working with older network gear as I do the new stuff. On a recent project I found myself needing to connect an old Cisco 2950G with a new Cisco 3750E and was running into issues getting the duplex settings configured correctly.

To keep a long story short I headed out with my crossover cable as I often do, connected the two switches together and could not get the two switches to run the same duplex without CRC errors.

Turns out a standard patch cable and the assistance of auto mdix on the 3750e is all you need.

On the 2950G I did the following
int fa0/1
speed auto
duplex auto

On the 3750E I did the following
int gig 1/0/1
speed auto
duplex auto
mdix auto

Suddenly I have two error free interfaces running 100/Full.

If you have run into this issue, you might want to give this a shot, it has worked for me every time I have tried it since stumbling onto this.

Windows 7 Compatibility

2010-08-13T17:49:00.002-05:00

If you have been dragging your feet and are now planning on making the move to Windows 7 here is a website you should check out to check to see if your existing hardware and software is compatible with Windows 7.

Windows 7 Compatibility