I have read pages about creating a domain controller on the web, in books, and even in classes. They all mostly use some sort of domain name example such as "microsoft.com" or "contorso.com" etc.. etc.. These examples are used in diagrams and doing any type of lab.

From time to time and very rarely, in books or on the web, I will see someone indicating that it would be best to use a domain name such as "microsoft.local" or ".lan" or ".office".

Their reason is to keep public domain names separate from local domain names. In which case the local domain will be more secure from the outside world.

However, bouncing back, I have see corporate diagrams that list their domain controller ".com" or ".edu".

My question is this: if it is more secure to use an non-internet domain extension, why does it seem that not everyone or hardly anyone is using this method.

Is it better in one sense to use a public extension and in another sense in using a private extension?

And which method would you most likely would use; public or private domain extension?
kvarnerexpress

for a start, only people on the local network can access the ".lan" or ".office" office domains, seems as the main server has them setup with DNS. noone from the outside can access them. I dont exactly see why anyone would want their own domain on their own private network, unless a school or college or something. They could simple use the comuter names or IP's

There are services on th web wwhere you can create your own domains, byt that requires the end user to download and install an extension into IE to be able to support them, simple to tell them where to look for misc domain extensions. There realy is no point in having myawesomesite.myext

Kind of wandering here a bit, but just going to make the following point about domain extensions.
There are now way more dot org names out there. It used to be reserved for "organisations", but it seems that even individuals are able to use them.
Should there be another extension for personal use? I'm thinking I need an extension like:
dot ref to let people know that I ref Hockey,
or dot gek to say I use a computer too much.

LOL

they are sure lots of domain extensions that arent really using for networks, organizations nor companys i mean i have a .NET domain and im not a network i just use it for personal stuff but since the registrants cant verify that you're a company, organizations, network and that stuff.. besides the other domain extensions are sometimes more expensive that the 'commercial' ones (net, org, com)

People use .lan or .office or .local for their domain since they won't need to register to get a domain. The domain isn't availible from outsider. Even if they have real domain it isn't alway the case that people will be able to access your network from outside, You would also need a REAL ip. (not private ips like 192.168.*.* or 10.*.*.* [I can't remember the Class B private ip though])