Configuring and Managing Network Components in Oracle^® Solaris 11.3

How to Create a Multihomed Host

1. Become an administrator.
2. Configure each additional network interface that was not configured as part of the installation process.

   Refer to How to Configure an IPv4 Interface.

3. If packet forwarding is enabled, disable this service.

   # routeadm -p ipv4-forwarding
   persistent=enabled default=disabled current=enabled
   # routeadm -d ipv4-forwarding -u
   # routeadm -p ipv4-forwarding
   persistent=disabled default=disabled current=disabled

4. (Optional) Turn on dynamic routing for the multihomed host.

   # routeadm -e ipv4-routing -u
   # routeadm -p ipv4-routing
   persistent=enabled default=enabled current=enabled

The following example shows how to configure a multihomed host, as illustrated in the figure in IPv4 Autonomous System Topology in Planning for Network Deployment in Oracle Solaris 11.3. In this example, the system has the host name hostc. This host has two interfaces, which are connected to two different networks.

To begin, you would display the status of the system's interfaces.

# dladm show-link
LINK     CLASS     MTU     STATE   BRIDGE   OVER
net0     phys      1500    up      --       --
net1     phys      1500    up      --       --

# ipadm show-addr
ADDROBJ        TYPE     STATE        ADDR
lo0/v4         static   ok           127.0.0.1/8
net0/v4        static   ok           192.0.2.3/27

The dladm show-link command shows that hostc has two datalinks. However, only net0 has been configured with an IP address. To configure hostc as a multihomed host, you would configure net1 with an IP address on another subnet, for example, the 192.0.2.32/27 network. Ensure that the underlying physical NIC of net1 is physically connected to the network.

# ipadm create-ip net1
# ipadm create-addr -a 192.0.2.35/27 net1

# ipadm show-addr
ADDROBJ        TYPE     STATE        ADDR
lo0/v4         static   ok           127.0.0.1/8
net0/v4        static   ok           192.0.2.3/27
net1/v4        static   ok           192.0.2.35/27

Next, you would add the net1 interface to the /etc/hosts file as follows:

# vi /etc/inet/hosts
127.0.0.1           localhost
192.0.2.3/27        hostc    #primary network interface for host3
192.0.2.35/27       hostc-2  #second interface

Then, you would turn off packet forwarding if this service is running on the hostc as follows:

# routeadm -p ipv4-forwarding
persistent=enabled default=disabled current=enabled

# routeadm
              Configuration   Current              Current
                     Option   Configuration        System State
---------------------------------------------------------------
               IPv4 routing   enabled              enabled
               IPv6 routing   disabled             disabled
            IPv4 forwarding   disabled             disabled
            IPv6 forwarding   disabled             disabled

           Routing services   "route:default ripng:default"

Routing daemons:

                      STATE   FMRI
                   disabled   svc:/network/routing/ripng:default
                     online   svc:/network/routing/ndp:default
                   disabled   svc:/network/routing/rdisc:default
                   disabled   svc:/network/routing/legacy-routing:ipv4
                   disabled   svc:/network/routing/legacy-routing:ipv6
                     online   svc:/network/routing/route:default

The routeadm command reports that dynamic routing through the in.routed daemon is currently enabled.