Microsoft Disable Netbios Option

[Anderson, Charles R]

You need to set the vendor-option-space.  You see, option 43 is "shared" among many different vendors and each vendor can have a different format for sub-options inside option 43.

For example, to set up the option space for APC vendor option codes, use this:

class "APC" { 
  match if option vendor-class-identifier = "APC";
  option APC.cookie "1APC";
  option server.vendor-option-space APC;
}

and for Microsoft, this should work:

option space MSFT;
option MSFT.disable-netbios code 1 = unsigned integer 8;
option MSFT.release-on-shutdown code 2 = unsigned integer 32;
option MSFT.default-router-ttl code 3 = unsigned integer 32;

class "Microsoft Windows" { 
  match if option vendor-class-identifier = "MSFT";
  option server.vendor-option-space MSFT;
}
class "Microsoft Windows 2000" { 
  match if option vendor-class-identifier = "MSFT 5.0";
  option server.vendor-option-space MSFT;
}
class "Microsoft Windows 98/Me" { 
  match if option vendor-class-identifier = "MSFT 98";
}


On Wed, Oct 10, 2018 at 04:09:00PM +0200, Meike Stone wrote:
> Hello dear list,
> 
> I try to configure "Microsoft Disable Netbios Option".
> If I use:
> option space MSFT;
> option MSFT.nbt  code 1 = unsigned integer 32;
> option MSFT.nbt 2;
> 
> nothing happens. The client has a acitvated the parameter "Netbios
> over TCP/IP" (seen with ipconfig) after getting the IP via DHCP. But
> the client sends in the discover in the "parameter request list"
> (option 55) the options 43, but the server doesn't sends the option 43
> back. (sniffed with wireshark)
> 
> If I remove the config from above and configure:
> 
> option vendor-encapsulated-options 01:04:00:00:00:02;
> 
> the client get's the option 43 from the server and the parameter
> "Netbios over TCP/IP" (seen with ipconfig) is disabled as expected.
> 
> Why is one configration working and the other not?
> 
> (all configurations are done in the global section, I use ISC server
> version 4.3.3 on SLES12SP3)