>>I'm seeing a lot of hits in firewall logs for DCs trying to establish sessions to clients on TCP139 (NBT Session Service). Does anyone know why this is happening or if it's necessary?


To your clients or is there just a firewall between your DC's and the clients on your trusted networks?

Have you checked to see if it's the computer browser that's initiating the calls?

Al



On 9/21/06, Brian Desmond <[EMAIL PROTECTED]> wrote:

Yeah I know about going client à DC. I'm trying to figure out why the *DC * is establishing connections to the client.

 

Thanks,

Brian Desmond

[EMAIL PROTECTED]

 

c - 312.731.3132

 

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of [EMAIL PROTECTED]
Sent: Thursday, September 21, 2006 6:05 AM
To: [email protected]
Subject: RE: [ActiveDir] DC Establishing Session to client on TCP139

 

netbios-ns      137/tcp    NETBIOS Name Service   
netbios-ns      137/udp    NETBIOS Name Service   
netbios-dgm     138/tcp    NETBIOS Datagram Service
netbios-dgm     138/udp    NETBIOS Datagram Service
netbios-ssn     139/tcp    NETBIOS Session Service
netbios-ssn     139/udp    NETBIOS Session Service

It's been a while, but you may find that all 3 are needed.

 

If memory serves - 137 is used to resolve names; 138 to send/receive data; 139 to establish and maintain the session.

 

 

neil


From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Paul Williams
Sent: 21 September 2006 09:30
To: [email protected]
Subject: Re: [ActiveDir] DC Establishing Session to client on TCP139

It's probably SMB (CIFS).  The NT5.x client service attempts to establish SMB sessions using both 445 and 137/8/9 (whichever one).  The first to reply is what is used.  If 445, it's SMB over TCP/IP.  If the NetBT 3, then it's SMB over NetBIOS over TCP/IP (NetBT).

 

Note.  It doesn't use all three of the NetBT3, I just don't remember what's what.

 

 

--Paul

----- Original Message -----

Sent: Thursday, September 21, 2006 2:53 AM

Subject: [ActiveDir] DC Establishing Session to client on TCP139

 

I'm seeing a lot of hits in firewall logs for DCs trying to establish sessions to clients on TCP139 (NBT Session Service). Does anyone know why this is happening or if it's necessary?

 

Thanks,

Brian Desmond

[EMAIL PROTECTED]

 

c - 312.731.3132

 

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