Re: TCP/IP Connection Status

What's port 445 used for in Windows 2000/XP?

Among the new ports used by Windows 2000, Windows XP and Windows Server
2003, is TCP port 445 which is used for SMB over TCP.

The SMB (Server Message Block) protocol is used among other things for file
sharing in Windows NT/2000/XP. In Windows NT it ran on top of NetBT (NetBIOS
over TCP/IP), which used the famous ports 137, 138 (UDP) and 139 (TCP). In
Windows 2000/XP/2003, Microsoft added the possibility to run SMB directly
over TCP/IP, without the extra layer of NetBT. For this they use TCP port
445.

At its simplest NetBIOS on your LAN may just be a necessary evil. NetBIOS on
your WAN or over the Internet, however, is an enormous security risk. All
sorts of information, such as your domain, workgroup and system names, as
well as account information is obtainable via NetBIOS. It really is in your
best interests to ensure that NetBIOS never leaves your network.

If you are using a router as your Internet gateway then you will want to
ensure that it does not allow inbound or outbound traffic via TCP ports
135-139.

If you're using a Firewall then you should also block the same ports - TCP
ports 135-139.

If you are using a multi-homed machine i.e. more than 1 network card, then
you should disable NetBIOS on every network card, or Dial-Up Connection
under the TCP/IP properties, that is not part of your local network.

As Always,
Robert G. Owens
owensr@xxxxxxxxxxxxxxxx
Programmer/Systems Admin.
Concord Fabrics, Inc

                    "nec scire fas est Omnia"
               it is not Gods will, We should know all
                           -----Horace-------

----- Original Message ----- 
From: "Dwayne Allison" <Dwayne.Allison@xxxxxxxxxxxxxxxxxxxxxxxx>
To: "Midrange Systems Technical Discussion (E-mail)"
<midrange-l@xxxxxxxxxxxx>
Sent: Monday, July 18, 2005 10:53 AM
Subject: FW: TCP/IP Connection Status


> What is port 445
>
> -----Original Message-----
> From: PRDALP?S10B0627@xxxxxxxxxxx [mailto:PRDALP?S10B0627@xxxxxxxxxxx]
> Sent: Monday, July 18, 2005 4:40 AM
> To: Alps Support Phone 2; Cathy Worthington
> Subject: TCP/IP Connection Status
>
>
>
>
> TCP/IP Connection 445 has been restarted
>
>
>
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