Check out the shareware NetInfo which will
- show all computers across the domain
- if you have the rights, show information about computers in trusted domains
- role of the computer, additional information
- server transports
- services
- devices
- sessions
- drives
- local groups
- global groups
- information about users
- network statistics
- open files
- shares
Definitely worth looking at the discovery phase of penetration testing. Could
be considered a baby hacker tool but it is very useful for your own testing.