[Samba] winbindd hangs and makes the system unuseable when DC is offline

[Felix Matouschek]

Hello,
 
I am using winbindd to map users via the idmap_ad backend from a Samba 4.2.2 AD to another machine in the network.
Everything works fine unless I shutdown the DC.
I would expect winbindd to realize the DC is offline and shutdown or something, however instead of realizing something is wrong 
It goes into some kind of reconnection loop and makes the whole system unuseable.
As soon as I kill winbindd or the DC comes online again everything goes back to normal.
 
Is there any option to limit the count of reconnection tries when a DC is offline? Or have I overlooked something perhaps?
 
My smb.conf looks like this:
 
[global]
    netbios name = MyServer
    server string = Fileserver (%h V:%v)
 
    workgroup = INTRANET
    realm = INTRANET.MYDOMAIN.DE
    security = ADS
 
    winbind enum users = yes
    winbind enum groups = yes
    winbind expand groups = 1
    winbind nested groups = yes
    winbind use default domain = yes
    winbind normalize names = yes
    winbind refresh tickets = yes
    winbind nss info = rfc2307:INTRANET, template
    template shell = /bin/bash
    template homedir = /home/users/%U
    idmap_ldb:use rfc2307 = yes
    idmap config * : backend = tdb
    idmap config * : range = 1000000 - 1999999
    idmap config INTRANET : backend = ad
    idmap config INTRANET : schema_mode = rfc2307
    idmap config INTRANET : range = 5000 - 40000
 
    map untrusted to domain = yes
 
    unix extensions = no
    invalid users = root, vipco-admin
 
    acl allow execute always = yes
 
    printing = bsd
    printcap name = /dev/null
    disable spoolss = yes
    load printers = no
 
    deadtime = 10
    use sendfile = yes
    socket options = TCP_NODELAY IPTOS_LOWDELAY SO_KEEPALIVE
 
Greetings,
Felix