network inaccessible

[Andrew Bartlett]

"Russell A. Bell" wrote:
> 
>         When the ISP goes down Windoze computers cannot map drives on
> the local SambaServer.  Windoze reports the network as busy and
> inacessible.  Non-SMB connections (e.g., telnet, ftp, ping) work; an
> instance of smbd -D appears on the process list for each machine
> attached; drives already mapped still work.  log.MachineNames report
> read_data errors when this happens.  Only asyncdns.c, a piece of
> nmbd's source, makes this call, and it uses it for DNS queries.  So I
> suspect that nmbd tries to call the external DNS at drive-mapping
> time, can't get through, and Windoze times out before nmbd gives up on
> the DNS query.  I don't see why this happens: why does SambaServer
> call an external DNS server?  We don't have 'dns proxy', 'wins
> server', or 'wins support' on.  If I use 'name resolve order =
> lmhosts, hosts', ommitting 'bcast' and 'wins', will nmbd not make an
> external DNS request?  Since lmhosts should resolve all requests and
> we use the default name resolve order now, I would have thought it
> would make no difference.  But perhaps some implicit external request
> happens that I have missed.
> 
> russell bell

Samba also does DNS lookups in client_name() - in lib/util_sock.c - and
this cannot (AFAIK) be disabled.  The best thing to do is to setup a
local DNS server for your network, at least so it gets a 'host not
found' earlier.  Or you could just list the hosts in /etc/hosts if its a
smaller network.

The name resolve order is primarily a client setting, its used when
samba needs to contact another server for some reason - not (AFAIK) when
answering requests.

Hope this helps,
Andrew Bartlett

-- 
Andrew Bartlett
abartlet at pcug.org.au