UPnP & NAT-PMP
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You can find the UPnP & NAT-PMP Settings at **Services → UPnP & NAT-PMP**.

.. image:: img/Services-UPNP.png
    :width: 100%
    :align: center
    :alt: UPnP

The **Universal Plug and Play** allows network devices to see each other on the network and establish a network connection.
While the **NAT Port Mapping Protocol** allows automatic configuration of address translation and port forwarding.

Both will create Firewall and NAT table entries automatically.

On the setup page it's possible to **enable** the service which is disabled by default.
You can enable the **UPnP Port Mapping** or the **NAT-PMP Port Mapping** as well as both.
The **External Interface** as well as a set of **Interfaces** can be set up.
With **Override External Address** an alternate external address to accept inbound connections, e.g. IP Alias or CARP Virtual IP address, can be setup.
**Default Deny** denies access by default. **Packet Log** enables the logging of packets.
**System Uptime** reports the system uptime instead of the daemon uptime. 
You can configure a **Custom Presentation URL** but by default the VT AIR URL will be used.
For the optional **Custom Model Number** the VT AIR firmware version will used by default.
Finally multiple **ACL Entries** can be configured.
Each entry is either allow or deny, has an **External and Internal Port**, an **IP Address** and an optional **Netmask**.
Otherwise devices will create NAT and Firewall entries without a way of controlling them.