Packages automagically modifies /etc/nsswitch.conf -------------------------------------------------- Previously the base-files package shipped /etc/nsswitch.conf and specified: hosts: files dns mdns However, due to bug#351990, this is no longer the case. /etc/nsswitch.conf is now generated post-installation. Upon installation of nss-mdns, if the strings 'mdns', 'mdns_minimal', 'mdns4', 'mdns4_minimal', 'mdns6' or 'mdns6_minimal' appear on the hosts line, your /etc/nsswitch.conf file will not be updated, otherwise it will updated to match the upstream recommended configuration which usually looks like: hosts: files mdns4_minimal [NOTFOUND=return] dns Other possible configurations ----------------------------- In versions older than 0.10-4 we used this configuration: hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 This looks in mDNS whenever a non-link-local address does not have a PTR (reverse DNS) record in DNS. If the host with that address is local and available in mDNS, this means it becomes reverse-resolvable, but if the host with that address is not local, it causes a 5 second delay, so this is no longer enabled by default. If a local administrator wishes to reinstate mdns4, they can do so. Sites with a .local DNS zone ---------------------------- Making nss-mdns authoritative for .local breaks resolution on networks where .local is a real domain name. To workaround this, avahi-daemon should be restarted when the DNS settings change (for example via resolvconf and dhclient hooks) and disable itself when a SOA for the .local zone is found. This is not currently implemented at the time of writing, but should soon be. See also this excellent summary on the upstream website: