content/operate/rs/7.4/networking/mdns.md
{{< note >}} mDNS is only supported for development and testing environments. {{< /note >}}
If you choose to use the mDNS protocol when [you set the cluster name]({{< relref "/operate/rs/7.4/networking/cluster-dns" >}}), make sure that the configurations and prerequisites for resolving database endpoints are met on the client machines. If you have [Replica Of]({{< relref "/operate/rs/7.4/databases/import-export/replica-of/" >}}) databases on the cluster, the configurations and prerequisites are also required for the Redis Enterprise Software nodes.
To prepare a client or node for mDNS:
Make sure that the clients and cluster nodes are on the same physical network or have the network infrastructure configured to allow multicasting between them.
Install these prerequisite packages:
For Ubuntu:
apt-get install libnss-mdns
For RHEL/CentOS 6.x:
$ rpm -ivh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
$ yum install nss-mdns
$ service avahi-daemon start
For RHEL/CentOS 7:
$ rpm -ivh https://dl.fedoraproject.org/pub/epel/7/x86_64/Packages/e/epel-release-7-12.noarch.rpm
$ yum install nss-mdns
$ service avahi-daemon start
If you are using [mDNS with IPv6 addresses]({{< relref "/operate/rs/7.4/networking/multi-ip-ipv6" >}}),
update the hosts line in /etc/nsswitch.conf to:
hosts: files mdns4_minimal
\[NOTFOUND=return\] mdns