NetBios is not really a Network
Protocol. Is rather a software system (API) to link a computer name (16 bit)
to an IP address. Initially developed by IBM, it uses the WINS
database bound Working
Groups. It is used in older networks Microsoft
(Win 95 - 98 - Me) together
with NetBeui.
Another method used by Microsoft Networks (2000 and Professional - business
versions later) use the Internet DNS (Domain Name
Service).
A comparison between DNS and NetBIOS required.
In the first case, the address of a computer is similar to that of an Internet
domain name. By cons, NetBios will help give a straightforward name to favorites
networks and sharing using type address \ \ computer \ shared folder.
This explains been shipped is still often used in current networks.
A NetBIOS name can include alphanumeric standard
(no accented characters, spaces, numbers, characters! @ # $% ^ & '(). - _ ()
~. It is limited to 15 characters.
This protocol is insecure and is currently used for
compatibility with older operating systems. It uses network
ports 135, 137, 138, 139 and 445 (both TCP in UDP). The port 445 is used by Windows
2000 and next (XP, 2003,
Vista ...)
135
Service Location (EMAP)
Used by procedure calls distances
137
NetBIOS Name Service
Used to check the names of computers in the
WINS database.
138
NetBios Datagram Service
Used as Broadcast
to detect if the name is actually on the network. Mainly used by the
"Network Neighborhood". This port is normally used in UDP
protocol.
139
NetBIOS Session Service
Used to share resources between computers
(printers, files, ...), normally only TCP port.
445
Netbios
Additional features established from
Windows 2000 (no millennium). This port uses more WINS
but a dynamic name service based on DNS (Active
Directory).
This protocol allows the sharing of resources in an
internal network. These ports are required to be closed on hardare firewall in Internet connection.
