docs/en-US/multiple-ip-nic.xml

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<section id="multiple-ip-nic">
  <title>Configuring Multiple IP Addresses on a Single NIC</title>
  <para>&PRODUCT; now provides you the ability to associate multiple private IP addresses per guest
    VM NIC. This feature is supported on all the network configurations&mdash;Basic, Advanced, and
    VPC. Security Groups, Static NAT and Port forwarding services are supported on these additional
    IPs. In addition to the primary IP, you can assign additional IPs to the guest VM NIC. Up to 256
    IP addresses are allowed per NIC.</para>
  <para>As always, you can specify an IP from the guest subnet; if not specified, an IP is
    automatically picked up from the guest VM subnet. You can view the IPs associated with for each
    guest VM NICs on the UI. You can apply NAT on these additional guest IPs by using firewall
    configuration in the &PRODUCT; UI. You must specify the NIC to which the IP should be
    associated.</para>
  <para>This feature is supported on XenServer, KVM, and VMware hypervisors.</para>
  <note>
    <para>You need to configure the secondary IP address on the guest VM. &PRODUCT; will
      not configure the acquired IP address on the VM. Ensure that you assign IPs to NIC each
      time the VM reboots.</para>
  </note>
  <para>Some of the use cases are described below:</para>
  <itemizedlist>
    <listitem>
      <para>Building network appliances: Network appliances, such as firewalls and load balancers,
        generally work best when they have access to multiple IP addresses on the network
        interface.</para>
    </listitem>
    <listitem>
      <para>Moving private IP addresses between interfaces or instances. Applications that are bound
        to specific IP addresses can be moved between instances. </para>
    </listitem>
    <listitem>
      <para>Hosting multiple SSL Websites on a single instance. You can install multiple SSL
        certificates on a single instance, each associated with a distinct IP address.</para>
    </listitem>
  </itemizedlist>
  <section id="workflow-rn">
    <title>Assigning Additional IPs to a VM</title>
    <orderedlist>
      <listitem>
        <para>Log in to the &PRODUCT; UI.</para>
      </listitem>
      <listitem>
        <para>In the left navigation bar, click Instances.</para>
      </listitem>
      <listitem>
        <para>Click the name of the instance you want to work with.</para>
      </listitem>
      <listitem>
        <para>In the Details tab, click NICs.</para>
      </listitem>
      <listitem>
        <para>Click View All.</para>
      </listitem>
      <listitem>
        <para>Click Acquire New IP, and click Yes in the confirmation dialog.</para>
        <para>You are prompted for confirmation because, typically, IP addresses are a limited
          resource. Within a few moments, the new IP address should appear with the state Allocated.
          You can now use the IP address in Port Forwarding or StaticNAT rules.</para>
      </listitem>
    </orderedlist>
  </section>
   <section id="caveats">
    <title>Port Forwarding and StaticNAT Services Changes</title>
    <para>Because multiple IPs can be associated per NIC, you are allowed to select a desired IP for
      the Port Forwarding and StaticNAT services. The default is the primary IP. To enable this
      functionality, an extra optional parameter 'vmguestip' is added to the Port forwarding and
      StaticNAT APIs (enableStaticNat, createIpForwardingRule) to indicate on what IP address NAT
      need to be configured. If vmguestip is passed, NAT is configured on the specified private IP
      of the VM. if not passed, NAT is configured on the primary IP of the VM.</para>
  </section>
</section>