Posts Tagged ‘Linux’

You can use tcpdump or wireshark but if you have a Linux box handy you can install: cdpr. It makes life easy like this:

cdpr -v

Just follow the prompts for selecting the interface and wait for the cdp transmission to come through. Understand that some values, like Native VLAN, are in hexidecimal and you’ll need to convert it to decimal. Otherwise, happy hunting.


A quick tidbit of information useful in troubleshooting and interviewing and reviewing the logs (if you can) before you start hacking away at the issue. It makes no sense to start diagnosing an issue if you have logs that can, hopefully, tell you what was going on before and after an event that caused an outage. For instance, if your wireless just decides to go down you may want to look at the lgos in the AP (autonomous mode) or the controller (Controller mode) and see what was happening. Given there is enough verbosity in the logs it should tell you what happened and you can take corrective measures. This applies to interviews because people always ask “What are your steps to figuring out what happened?” I always start with: I check the logs.


If you’re running out of space on a Windows Server 2003 instance in VMware you do have a workaround to expand your system partition. This will require gparted which is standard on Knoppix so I would suggest you grab a copy of Knoppix and burn that to a CD first. Now I will detail the steps required since this is really easy:

  1. Power off the VM
  2. Right click your VM in vSphere client – Edit Settings
  3. Select the Hard Disk that contains the VMDK file for your system drive
  4. Increase size to whatever you want (or is available)
  5. Open the Console to the VM
  6. Power on the VM but quickly mount your local host CD/DVD drive to boot to Knoppix
  7. Once Knoppix is booted open a terminal and type in: sudo gparted
  8. Select the drive you want to expand by right clicking and select “Resize”
  9. You can resize by typing in the desired size or dragging the vertical bar over to desired size
  10. Continue through the menu and when done press APPLY at the top and gparted will do the work
  11. Once complete, reboot the system and remove the Knoppix CD and unmount the CD drive from within vmware
  12. LET WINDOWS PERFORM THE CHECKDISK – DO NOT INTERRUPT THIS PROCESS
  13. Windows will probably want to reboot when you login, please do so and after this you’ll see your newly sized system partition

http://www.itworld.com/open-source/284553/linux-culprit-leap-second-lapses-cassandra-exec?source=ITWNLE_nlt_countdown_2012-07-03

While I am a Open Source user and believer, this should have been taken care of a lot sooner, I guess it finally shows that Linux isn’t as bullet proof as once thought to minor annoying issues that cause administrator headaches.


How often do we run into problems and have to contact a third party vendor to get the resolution only to spend a large amount of time getting someone (sometimes ourselves) to stop the blame game and start working together? This seems to happen all the time in the IT field and this is frustrating as all hell and we as IT professionals and engineers need to put our ego and pride aside and work on the problem to benefit our customer and I’ll share my thoughts on the various scenarios… Read the rest of this entry »


Just though I would put this out there for the world to read…use new network cables! If the cable doesn’t have a locking clasp you’re begging to have someone just brush by and jiggle it loose and then you’re troubleshooting an issue that looks complex when in reality all you have to is plug in a cable! ALWAYS USE NEW CABLES


We see it all the time here in the IT field…people floating around aimlessly during a maintenance doing nothing while others seem to be working harder than others. Why is this? For the most part I don’t believe we should be blaming them directly; rather, I think we need to blame management for not delegating responsibilities properly and efficiently… Read the rest of this entry »


While I never recommend the use of Superscopes as they are usually relevant to a bad network design. I know that sometimes networks are inherited and not the fault of the person having to perform this action;thus, I am going to provide a lean set of steps to configure this assuming you know your way around Microsoft DHCP server and have a few requirements met: Read the rest of this entry »


Let me start by saying that Superscopes are not a standard mechanism of DHCP, just a “hack” by Microsoft to support networks that don’t understand the concept of “1 IP subnet PER vlan, not 10 IP subnets per VLAN”. The only, and I do mean ONLY, time that you use Superscopes is when you have a network design that has multiple IP subnets inside the same VLAN. Let me explain the ONLY instance where this is needed and WHY you need multiple interfaces configured for this to work… Read the rest of this entry »


So there is the long standing debate of GUI Vs CLI in both the server and Networking world. There are quite a few angles to argue and I know that in this one single post I am not going to cover 100% of them and I am going to keep emotion out of this and stick to the facts and try to do a “Qualitative review of the two Read the rest of this entry »