DHCP discovery of WINS servers

[Shirish Kalele]

>> > - we don't want to be doing a dhcp operation for *every* client
>> >operation.  While its fine to do it each time the server starts, doing
>> >it every time a client (like smbclient) starts could be a little
>> >overkill.
>> 
>> We don't. Only nmbd gets a list of wins servers to use when it starts up
>> the first time. smbd and smbclient or any other program doesn't do any
>> dhcp.
>
>If so, then how does smbclient discover its WINS server?  Same for 
>nmblookup?  These tools need to have a WINS server and (I think) they 
>currently get their WINS server by reading smb.conf.
>
Yep, you're right. I guess we'll need to save the list discovered in a
file, along with any lease time. If the wins server entry has dhcp in it,
we look for the file. If it doesn't exist or if it is too old (based on
the lease time or our own arbitrary limit), we rediscover the wins
servers. This could go for the client tools as well as nmbd.

>> > - what if our request is lost?  UDP is lossy, should we at least make
>> >some attempt to send a second request?
>> 
>> The more attempts we make, the longer nmbd will take to start doing its
>> job: registering names and workgroups with the network and wins server. At
>> least, with the way the dhcp stuff is implemented right now.  
>
>Yes, but if we don't get an answer then we don't have a WINS server.  That
>puts us in "B" mode.
>
>I suppose we could use the list delimiters in loadparms to do something 
>like this:
>
>  wins server = dhcp | 192.168.10.34 : 10.73.199.18
>
>The idea is "try DHCP first, but if that fails use this list of IPs". 
>(I'm not sure about the '|' delimiter but you get the idea.)  That further
>suggests something like this:
>
>  wins server = dhcp : 192.168.10.34 : 10.73.199.18
>
>which (noting the delimiter change) would retrieve the WINS list from 
>dhcp and add the additional IPs to the end of the list.  List order is 
>significant in WINS Failover.
>
I think that would work nicely. I'll try and put these changes in whenever
I can next. 

- SK