network groups?
 

Is linux in some network group after it is installed, like windows?

(eg, by default in windows it's 'workgroup')

presumably you mean for cifs / smb and all that junk. this is handled totally by samba, so it's up to you to configure samba appropriately. There's no concept of workgroups embedded in linux as a whole, as it's not a Micro$oft product...

i assume then that i configure it by a line 'workgroup = xxx' in smb.conf

Thanks.