Je ne connaissais pas, surtout le mot-clé « multi » : « If set to on, the resolv+ library will return all valid addresses for a host that appears in the /etc/hosts file, instead of only the first. This is off by default, as it may cause a substantial performance loss at sites with large hosts files. »

Et en vrai, ça se rencontre dans ce genre de cas : https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=723915 ... joie ...