If you are like me you enjoy a good prank every now and again. It’s fun to outsmart a coworker, get them frustrated for a minute or two and the go on with your day. I have had a few pranks played on me as well and figured I would share a few of them here for entertainment sake. Not all of these are original but some are (as far as I know). Since this is a networking website the pranks are network related. I suggest NEVER doing any of these on production systems. You may laugh but your boss may not to the point of asking you to find another place to work. YOU HAVE BEEN WARNED!
I am going to just set these up conceptually but not go specifically into the configuration. If you are not familiar with how to perform these configurations and understand the in’s and the outs of how they work you probably shouldn’t be doing these pranks anyway.

Web Site Surprise

Does one of your coworkers like to check some obscure website daily? Why not surprise them with a different site altogether some day? To do this you will need to make the “prank” page with a funny message, etc. Additionally, you will need to a dedicated webserver to load it on. Finally, you will have to manually created a DNS record for the site they typically visit pointing it instead to your special purpose web server. As stated above; know the risks! Be sure your targeted user is in fact the only person that uses the web page you are picking on. This was played on me in the past as I tried to access http://technologyordie.com. I received a “Your Site Has Been Hacked” message, and naturally flipped out until I attempted to connect to make administrative changes and realized the name resolution trick was in place…

Web Site Redirect

Another prank that I have not performed but conceptualized is to redirect a single (or multiple) users web traffic to a proxy. WCCP on Cisco routers allows you to ACL the users you would like to apply the redirection to making it very prank friendly. Configure a WCCP enabled proxy to server up pages of your choosing as before. Perhaps you would like to use the Proxy to flip images, rewrite URLs, etc. You could also manipulate the name resolution settings of the proxy server and combine it with the first prank. A final way to do this same trick in a different manner would be to use policy routes and send a user’s web traffic over another interface that traverses a proxy. Again and as always, know 100% what you are doing and only do this in a lab environment!

Rate Limit of Death

The third prank is to rate limit a user to a very very low rate of throughput. With careful planning you can have a coworker living the Dialup dream all over again. You of course cannot (or maybe there is a way?) introduce the high latency but horrendous throughput is always enough to get nearly anyone worked up. With extended ACLs you should be able to get very specific about what traffic works at what speeds. Just for ideas sake you could limit internet radio traffic to the point of cutting in and out without changing other functionalities.

Bad CDP Neighbors

When you know a colleague is documenting, T shooting, etc it can be simple and quick to run a CDP traffic generation script from your system while connected to the switch that are connected to. Run the script and advertise your system with a name that will stand out to the targeted individual.

Message Waiting On

On Cisco and other phone systems there is often an extension, that when dialed from a phone, enables the Message Waiting Indicator. Dial this number form the coworker’s phone when he/she is away and wait for them as they check their voice mail to an empty inbox.

Instant Log Off

You can set the timeout on a router or switch VTY line to a few seconds. When a user connects they are nearly instantly logged off. It’s really annoying! Make sure you have a way back into the device because there will need to be a way to undo this…

Cabling Annoyance

Manipulate a patch cable in such a way that the link lights still light but data will not flow. There are ways to put Switches in an always up port status as well…

Annoying Messages I

Enable the messenger service on a coworkers system and send them random messages while they are working. It’s sure to get their attention!

Annoying Messages II

When a coworker is logged onto a switch or router log in as well and send messages to the VTY line they are connected to.

Banner / MOTD Greeting

Make a custom ASCII art banner and enable it on a switch, router or Linux system for a coworker to be greeted by. Some platforms allow username variables as well so be sure to utilize any of those should they be available.  This can be a good place to try some of your ASCII art as well…

Auto Answer

Set your phone / soft phone to auto answer and have some type of music playing. You could replace the microphone with an MP3 Player, for instance. I have not tried or looked into this but if you can initialize the playing of an audio file when it answers there could be some comic value in that…
I hope everyone got some ideas form this. Again, I take no responsibility in how you use this information and anything outside of a lab is 100% on you!