You've just inherited an undocumented network: Now what?

One of the most difficult situations any administrator can encounter is inheriting an existing network with little or no documentation. Often, this means that you have to build your own documentation and map out the network yourself. These tips will help.

An inheritance is usually a good thing. Like your Aunt Bertha’s pie recipe or your Great Uncle Fred’s fortune. However, when you inherit someone’s undocumented network, you may feel pure, unadulterated dread—and rightly so.

Maybe it doesn't sound that frightening. But if you’ve ever been in such a situation, you've probably experienced a fear of the unknown that rivals any horror movie. For the benefit of those who have never taken over an undocumented network, I'll present a chilling tale that illustrates what you're likely to be up against. Then, I'll share some tips to help you come out on top.

Packratt's Network Tips
Longtime TechRepublic member David Packman (screen name packratt) is known for his frequent contributions to discussions in various parts of our site. His posts are renowned for being insightful and candid, so we talked him into doing some formal writing for TechRepublic. He now regularly shares his network tips in this column.

It was a dark and stormy night…
Imagine, if you will, a place where you have just been hired to take over a network, a network of great complexity with nobody around to explain what you see and no documentation to describe its workings. A problem occurs, and everyone turns to you to remedy the situation. Luckily, you’ve done this before. Yet when you attempt to repair the problem, your old bag of tricks fails you. It takes twice as long to apply the fix, and the network is down the entire time. You feel like a failure. It seems that everyone looks at you as though it was your fault, since the previous person fixed problems a lot faster than that.

Another week goes by, and you are asked to apply a change to the network that should be simple. Again, it’s something you’ve done many times before. That night, you go in, and the manager is with you because he wants to see how this is done. You make changes that should work just fine, and they stick. But then something else begins to fail—something that shouldn’t even have been associated with the change you made. You spend hours tracking down the problem. It turns out to have been caused by a dependency on the system you changed, which you didn’t see coming. The upgrade took all night and three times as long as you anticipated, and your manager was there to see yet another failure.

Why did this happen? How do you explain your difficulties? Does this scare you yet? Well, this isn’t just a campfire story; many of us have gone through it. We happened upon a nonstandard and undocumented network, and the terror was quite real. Lack of documentation, coupled with all of the ways a network can be designed and implemented, is a formula for confusion and frustration. So what can you do to turn things around? Here are a few tips that you might find helpful if you find yourself trapped in the twilight zone of an undocumented network.

Review and document
The first thing you should do is review the network. Browse around and try putting yourself in the mindset of the person or people before you in order to figure out why things are set up they way they are. If possible, collaborate with the people involved previously, since they can offer you insights to the things you don’t understand. Sometimes there is a method to something that seems to be the product of madness.

After your review, you should document what you find, from mapping out the network in a program such as Visio to writing down some of the first things you would like to change. Lack of previous documentation is no excuse for not documenting a network once you are in charge of it.

Plan and coordinate
Now that you are getting familiar with the new network, it’s time to bring all that documentation into play by planning the changes you believe are needed to stabilize your new network. Make sure that you plan well not only by thinking about what needs to be done but also by reasoning if and why it really needs to be changed.

Research your findings so that you can get the backing of your management team in making these changes. The team's backing will be essential when downtime and budgets need to be approved, so plan to show why it makes business sense to change how things are done.

While this is the first part of coordinating your assault on the undocumented network, you might also want to acquaint yourself with the other people on your team and in other departments that may be helpful to your cause. From the people who can help on the technical side to the people who will be affected by the changes you make, the more people who buy into your plan the better.

Attack and document again
Now is your chance to take ownership and start the long road of turning what was once another person’s work into your own legacy. Make sure that you take the time to get things right, since you’ve planned everything carefully by reviewing and researching, and you’ve done the extra work of getting everyone on board.

Don’t let all that effort go to waste by getting lazy now. Be sure that you document the changes you made, how you made them, and why you made them. Your coworkers and managers will be amazed by how well you have things running and how easy it is to follow up on your efforts. And by investing a little extra work and forethought, you can avoid leaving behind a horror story for your successors when you move on to a bigger and better position.

What tips do you have for documenting a network?
Have you ever inherited a network? How did it go? We look forward to getting your input and hearing about your experiences regarding this topic. Post a comment or a question about this article.


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