JLdL 08Apr16. ATTENTION! Some qmail-related packages hard-code UIDs and GIDs within the package and are machine-specific. Do not keep them and do not install them on another machine! This is NOT the case with the qmail package itself. However, the servers in the cluster where all configured, in Debian 8, with exactly the _same_ set of qmail-related UIDs and GIDs so that the packages compiled here can be installed in any server. Recipe to do it from sources: install the qmail-src package and then run the script build-qmail