Navigate to the area where you originally configured the external routable subnet.

1. On the menu bar, click Fabric > Inventory .

2. In the Navigation pane, click Pod Fabric Setup Policy .

3. On the Fabric Setup Policy panel, double-click the pod where you originally configured the external routable subnet.

   The Fabric Setup Policy for a POD page for this pod appears.

4. Locate the information for the subnets or TEP table, depending on the release of your APIC software:

   • For releases prior to 4.2(3), locate the Routable Subnets table.

   • For 4.2(3) only, locate the External Subnets table.

   • For 4.2(4) and later, locate the External TEP table.

Locate the external routable subnet that you want to delete in the table and determine if the state of that subnet is set to active or inactive .

1. Double-click on the entry in the subnets or TEP table for the existing external routable subnet that you want to delete.

2. Change the state for the subnet to inactive , then click Update .

Delete the existing external routable subnet.

1. Click on the entry in the subnets or TEP table for the existing external routable subnet that you want to delete.

2. Click the trashcan icon at the top of the table, then click Yes in the pop-up confirmation window to delete the external routable subnet.

Wait for at least 30 seconds, then configure a new external routable subnet.

1. Click + in the subnets or TEP table to configure a new external routable subnet.

2. Enter the IP address and Reserve Address, if necessary, and set the state to active or inactive .

   • The IP address is the subnet prefix that you wish to configure as the routeable IP space.

   • The Reserve Address is a count of addresses within the subnet that must not be allocated dynamically to the spine switches and remote leaf switches. The count always begins with the first IP in the subnet and increments sequentially. If you wish to allocate the Unicast TEP from this pool, then it must be reserved.

3. Click Update to add the new external routable subnet to the subnets or TEP table.

4. On the Fabric Setup Policy panel, click Submit .

Verify that the new routable IP address is configured correctly.

                  apic1# 
                  avread | grep routableAddress
               

routableAddress   14.3.0.228              14.3.0.229              14.3.1.228

Check the NAT entries created on the spine switch.

                  spine1# 
                  show nattable
               

                  -----NAT TABLE---------
                  Private Ip  Routable Ip
                  ----------  -----------
                  10.0.0.2    14.3.0.229 
                  10.0.0.1    14.3.0.228 
                  10.0.0.3    14.3.1.228