What is the effect of setting 'preferred master = yes' in a Samba configuration file?

Setting 'preferred master = yes' in a Samba configuration file specifically instructs the nmbd service to attempt to become the master browser upon startup. In a network where multiple devices compete to become the master browser, nmbd recognizes this setting as a directive that indicates its desire to take precedence in this role. This means that when nmbd starts, it will announce itself in the network as a capable master browser, effectively leading other devices in maintaining a list of available resources and services.

The configuration line indicates a proactive stance in the browser election process. While the master browser designation can be contested through the election process, marking 'preferred master = yes' provides a higher likelihood that nmbd will be elected as the master browser, particularly if it is set to have a high operating system level or can outbid other candidates during the election process. The effectiveness of this setting, however, may be influenced by its interaction with other settings such as 'local master', but when 'preferred master' is active and properly configured, nmbd can indeed take on the master role readily.