I am reviewing the security of a (quite large) network. There are a some thousands switches, several hundred routers, several hundred access points, tenths of FW, IPS, and so on. PCs and servers are on the bazillion side of the scale.
I have asked the network responsibles (not actual admins) for network maps for weeks and got some very high-level drawings on PPT and a few level-2 visios for some network segments. I had to figure out the location of security elements from config files and monitoring tools that do not cover the whole network.
I have always been told that a good admin needs to keep up to date documentation of his/her realm that being, servers, network or whatever is getting paid to admin. While I was an admin I tried to work by that rule.
So, right now, these resposibles tell me that keeping a network map with some level-3 detail, basic security elements, extra documents about IP addressing and defined VLAN is too much information for them to keep it updated so they decided not to generate that documents and rely on personal knowledge and monitoring tools that partially cover the network.
Personally I feel those are just a bunch of excuses, even with that network size, since it took them weeks to identify crucial information. Even though, I would like to know from the community examples of how these documentation has proven being useful on: - Business as usual management. - Technical events such as networks outages. - Security events.
I never administered a network this size so I might be wrong and the responsibles' point might be valid so, if you think so, could you please give actual examples of how really big networks are documented for admin's sanity and efectiveness?
Which would be valid alternatives to up-to-date network maps?