from the longer text in that report 'I cannot differentiate when samba is in use or idle when the client is Ubuntu, only when it is Windows.'
Nothing has happened to that report, so I am escalating here
Set the "deadtime" parameter on the server appropriately.
OK, installed that. It does force a disconnect.
The first time I try to reconnect I get an error "Unable to read", presumably the client doesn't know its friend has died. The second time I connect OK.
Not been able to try that with a windows client, but it does resolve the problem with the ubuntu client.
Well, if the client can't deal with that it's a client bug. Your workaround is to remove the deadtime parameter again and live with the long-living connections. There's nothing Samba can do about that.
Confirmed that the parameter change does not break connectivity from WinXP.
Thanks for the clue.