Trace cables the easy way with Cisco CDP on Windows

No matter how good your network diagrams are, sometimes you need to verify the port your server/desktop is in. Cisco Discovery Protocol is a great tool for network admins when you need to quickly map routers and switches, and if you’ve got an ESX server connected you’ll see that it picks up CDP info too – but the vast majority of my managed systems are Windows.

Here’s how to use TCPDUMP by Micro Olap to extend that functionality to your Windows boxes.

Firstly you need to find the interface number of the network adaptor you are trying to find CDP data for.  Use this command:

tcpdump -D

Which gives you a list of the interfaces on the computer:


My actual NIC is the third one in the list, so I can run the command:

tcpdump -i 3 -nn -v -s 1500 -c 1 ether[20:2] == 0x2000

-i n [interface and the number in the list, for me 3]

-nn [don’t resolve DNS, speeds things up]

-v [verbose mode, otherwise we won’t see all the packet details]

-s 1500 [set the maximum packet size to capture, the MTU is 1500 by default so it will capture the entire packet]

-c 1  [Capture one packet only, since we only want the CDP packet and filter using the header]

ether[20:2] == 0x2000 [Check the Ethernet header packet ID for the hex value 0x2000 – CDP protocol]


Some output is omitted, but you can see that the name of the switch and the port are both in there.

Easier than tracing a cable!

How to enable hot memory add on vSphere and ESX 4.0 after upgrade

So you’ve upgraded your ESX 3.x servers to 4.0 and you’ve upgraded your vCenter server, now you want to access the shiny new hot-add feature to upgrade some running server’s memory. Except you can’t, the feature is no-where to be seen. Something to bear in mind though, your OS needs to support hot-add, so you’ll need a Windows Enterprise or Datacenter edition.

Here’s how to enable it:

Upgrade the VM’s tools, if you haven’t already. This requires a re-boot, but don’t reboot, shut the server down down, otherwise you’ll require another reboot to add the feature. The tools can be upgraded from the system tray icon.image



Once the VM is shut down, upgrade the Virtual Hardware (again, assuming you haven’t already!)image








Once your virtual machine is fully up to date with VMTools and Hardware, you can edit the Advanced options (again, while the machine is shut down) and enable the feature.image









Now with the server booted, you can add Memory and CPU without the need for a reboot. In my tests changing the Memory from 1GB to 2GB caused a single dropped ping, and changing from 1 vCPU to 2 vCPUs caused a ping to drop.

image image

Upgrading Server 2008 RTM-SP2 to Server 2008 R2

If you read the Microsoft blurb for R2, the first thing you notice is that Server 2008 R2 is 64-bit only(!). It seems Microsoft are forcibly removing 32-bit server hardware from the data centre. I’ve not seen a decent upgrade guide online so far, so here’s my process.

I’m going to be upgrading a Server 2008 R2 x64 SP2 Standard Edition virtual server to R2. To see what editions can and can’t be upgraded, check out this Technet Article, but it’s safe to say that you can’t upgrade across architectures (32-bit to 64-bit) and you can’t downgrade SKUs (Enterprise to Standard).

The first step, as ever, is always to back up your server, if the upgrade goes wrong, you can always restore and try again. You have been warned!

So, without further ado, slip in your R2 DVD and begin…

image Install

image Update

image Select your target SKU

image Select “upgrade” (obviously :)

image Check your upgrade report (which is saved as HTML on your desktop. The first time I ran this it said that I didn’t have enough free space – it required a whopping 15GB, which makes me think that this is no Server 2003 –> R2 upgrade, it’s the full blown OS install. Assuming everything checks out, go ahead.

image Sit back and grab a cup of coffee. After a while, you’ll reboot

 image and the upgrade begins in earnest. Once the process is completed, and another reboot has happened, you’ll be upgraded to R2. You’ll need to activate it with your R2 key.

image Once you’re activated, update your server using Microsoft update or your patching method.

image Et voila!

CCNA Qualified

ccna_medAfter some pretty heavy investment in terms of time and money, I’ve passed my ICND2 exam and am now qualified as a Cisco Certified Network Associate (anyone else find it odd that you’re not even considered a professional by Cisco at this level?!)

I do consider the Cisco qualifications as significantly more valuable than the others that I hold, simply because of the difficulty of the exams. I do find them “honest” in that they’re not trick questions, and you don’t need a technique to pass – just in depth knowledge.

Anyway, I think I’ll take few weeks before I look to my next study/exam.

BlogEngine.Net 1.6 is released – and I’ve upgraded! Also migrated to IIS 7

I’ve just upgraded to BE.Net 1.6, and I thought I’d migrate to GoDaddy’s IIS 7 servers at the same time. The theory is that this would be a an easy migration and I’d have the weekend to iron out any bugs. Not so.

After testing on my local IIS 7 and working perfectly, I uploaded the updates to my live blog and hit the “Migrate to IIS 7” button, which promises it will be completed in 24h. I received the “update your DNS” email, and duly updated my A records to the new server, and the transfer seems to be ok – aside from the fact that viewing any specific post causes an error – I’m guessing with the permissions of the App_Data folder. The catch being that I can’t access my IIS settings until GoDaddy have completed their 24h migration process.

It’s now been more than 72 hours since I kicked of the migration and still I cannot access and fix the IIS permissions issue which is dogging my blog. I’ve emailed twice and am still waiting for some resolution. Perhaps I won’t be renewing this year?