Organizations should have LANBooks. A single place where a document or documents are kept with your network information. Whether it is when you bought those computers and what the specs and warranty are to the set up information for your DSL modem that is stuff you need to know.

Don't make your organization dependent on a technical person from the outside for that information. Ask them to type the information up and give it to you in case you need to use it some day when they aren't around.