[Samba] Hostname resolve fails after upgrade from 4.2 to 4.5

[Uri Simchoni]

On 05/11/2017 04:40 PM, Guru Prasad via samba-technical wrote:
> Hi All,
> 
> Just have few queries related to resolving the hostnames with the newer
> samba versions (4.5.x) Previoulsy i have used samba 4.2.x.
> 
> I have compiled and installed samba 4.2 in my debian machine.
> At the end i have "smbd" and "nmbd" daemons running in my machine.
> 
> I could perform all cifs related functionalities (along with ping,
> mount.cifs command) with both hostname and ip address.
> For example,
> ping debian-gp will work fine
> mount.cifs //debian-gp/Music /mnt/SMB/mt_point1 works fine
> 
> But few days back i have upgraded samba to 4.5.x
> I had both "smbd" and "nmbd" running in my machine
> But one thing i noticed is i could perform all samba functionalties with ip
> address and not with hostname.
> ping ip address and mount command with ip address works fine
> But if i use hostname instead of ip address in the above scenario, it says
> "Unable to resolve"
> I have not done anything other than upgrading samba from 4.2 to 4.5.
> But after 4.5 upgrade "ping" and "mount.cifs" is failing with hostname.
> ping debian-gp says "unknown host"
> mount.cifs //debian-gp/Music /mnt/SMB/mt_point1 works fine says "Unable to
> resolve"
> 
> Please let me know if i have missed anything here.
> 
> Thanks
> Guruprasad
> 

See https://www.samba.org/samba/history/samba-4.4.0.html.

Since Samba 4.4.0, the "wins" nsswitch module, which does the netbios
name resolution, has been rewritten to be a proxy to winbindd. This has
the benefit of making the module (which loads into any executable) more
lightweight, and also fixes and prevents some issues. However, it does
require winbindd to be running, in order to serve the requests.

I hope that helps,
Uri.