10.7 How does the package management system deal with packages that contain configuration files for other packages?
Some users wish to create, for example, a new server by installing a group of
Debian packages and a locally generated package consisting of configuration
files. This is not generally a good idea, because
dpkg will not
know about those configuration files if they are in a different package, and
may write conflicting configurations when one of the initial "group"
of packages is upgraded.
Instead, create a local package that modifies the configuration files of the
"group" of Debian packages of interest. Then
the rest of the package management system will see that the files have been
modified by the local "sysadmin" and will not try to overwrite them
when those packages are upgraded.