Samba4 internal dns Failed DNS update

[steve]

Hi
Version 4.0.0alpha19-GIT-0971a4e

After around 1/2 hour:

../source4/dsdb/dns/dns_update.c:294: Failed DNS update - 
NT_STATUS_IO_TIMEOUT

and everything stops.

304 - 327
static void dnsupdate_nameupdate_done(struct tevent_req *subreq)
{
     struct dnsupdate_service *service = tevent_req_callback_data(subreq,
                         struct dnsupdate_service);
     int ret;
     int sys_errno;

     service->nameupdate.subreq = NULL;

     ret = samba_runcmd_recv(subreq, &sys_errno);
     TALLOC_FREE(subreq);
     if (ret != 0) {
         service->nameupdate.status = 
map_nt_error_from_unix_common(sys_errno);
     } else {
         service->nameupdate.status = NT_STATUS_OK;
     }

     if (!NT_STATUS_IS_OK(service->nameupdate.status)) {
         DEBUG(0,(__location__ ": Failed DNS update - %s\n",
              nt_errstr(service->nameupdate.status)));
     } else {
         DEBUG(3,("Completed DNS update check OK\n"));
     }
}

Fine until then.
Any ideas?
Thanks, Steve