Ubuntu – Samba share not accessible by IP address, is by hostname

I am curious what kind of firewall setup you have, and if it differs on your production and non-production systems. According to here, these are the ports you need to allow:

netbios-ns 137/udp # NetBIOS Name Service
netbios-dgm 138/udp # NetBIOS Datagram Service
netbios-ssn 139/tcp # NetBIOS Session Service
microsoft-ds 445/tcp # Microsoft Directory Service

If you have some of these set up, but not all of them, it could explain why you get the password authentication box but then it can no longer communicate with your samba system.

From http://blog.realcomputerguy.com/2010/12/samba-and-guest-shares-with-security.html?spref=tw

In a nutshell you need:

• A username map file.
• A valid 'nix "guest" user mapped to the Windows guest account ("nobody" in most distros).
• Proper smb.conf configuration.

In this example our username map file is /etc/samba/smbusers. It maps a 'nix user to a Windows user.

In /etc/samba/smbusers (many distros include this file, but with the default commented out):

nobody = guest

In /etc/samba/smb.conf:

[global]
   ...
   security = user
   Map to guest = Bad User
   username map = /etc/samba/smbusers
   ...
-- no 'valid users =' line --

[theshare]
   ...
   guest ok = yes
-- no 'valid users =' line --