When running Samba file sharing services on CentOS (specifically smbd version 3.5.5-68.fc13 in this case), you might encounter persistent error messages in /var/log/messages related to failed CUPS connections. These errors typically appear as:

Nov 30 18:49:34 big03 smbd[9927]: [2010/11/30 18:49:34.850620,  0] printing/print_cups.c:108(cups_connect)
Nov 30 18:49:34 big03 smbd[9927]:   Unable to connect to CUPS server localhost:631 - Connection refused

Samba comes with printer sharing capabilities enabled by default. Even when you only need file sharing functionality, the service continuously attempts to connect to CUPS (Common UNIX Printing System) on port 631. When CUPS isn't installed or running, these connection attempts fail and generate log clutter.

The most effective approach is to modify Samba's configuration to disable printing support entirely. Edit your /etc/samba/smb.conf file with root privileges:

sudo vi /etc/samba/smb.conf

Add or modify these parameters in the [global] section:

[global]
    load printers = no
    printing = bsd
    printcap name = /dev/null
    disable spoolss = yes

After saving the configuration file, restart Samba services:

sudo service smb restart
sudo service nmb restart

Check your logs again - the CUPS-related error messages should no longer appear. You can verify active Samba configuration with:

testparm

For servers purely dedicated to file sharing, consider this streamlined configuration that completely excludes printing components:

[global]
    workgroup = WORKGROUP
    server string = File Server
    security = user
    map to guest = bad user
    dns proxy = no
    load printers = no
    printing = bsd
    printcap name = /dev/null
    
[shared]
    path = /path/to/shared/folder
    browsable = yes
    writable = yes
    guest ok = yes
    read only = no

Remember that these changes only affect new Samba connections. Existing connections might need to be terminated before the changes take full effect. For production environments, consider testing during maintenance windows.

If you later decide to enable printing support, simply reverse these changes and ensure CUPS is properly installed and running.

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When running Samba file sharing services on CentOS for Windows clients, you might encounter these frustrating messages flooding your /var/log/messages:

Nov 30 18:49:34 big03 smbd[9927]: [2010/11/30 18:49:34.850620,  0] printing/print_cups.c:108(cups_connect)
Nov 30 18:49:34 big03 smbd[9927]:   Unable to connect to CUPS server localhost:631 - Connection refused

Samba (smbd) by default includes printer sharing capabilities through CUPS integration. Even when you don't need printer sharing, the daemon still attempts to establish connections, causing these errors when CUPS isn't running.

Edit your Samba configuration file (/etc/samba/smb.conf) with root privileges:

sudo nano /etc/samba/smb.conf

Find or add these directives in the [global] section:

[global]
    load printers = no
    printing = bsd
    printcap name = /dev/null
    disable spoolss = yes

This configuration does three important things:

1. Prevents Samba from loading printer support
2. Sets a dummy print system (bsd) that requires no actual backend
3. Completely disables print spooler functionality

After making changes, verify your configuration syntax:

testparm

Then restart Samba services:

sudo service smb restart
sudo service nmb restart  # if using NetBIOS

For a more permanent solution, you can recompile Samba without printer support:

./configure --disable-cups
make
make install

This approach eliminates all printing-related code from the binary.

Check your logs after implementation:

tail -f /var/log/messages | grep smbd

You should no longer see CUPS connection errors, and your file sharing functionality will remain unaffected.