Interface configuration

All traffic in OPNsense travels via interfaces. By default, WAN and LAN are assigned, but many more are possible, like GUESTNET (captive portal) and PFSYNC (high availability).

Assignments

Most interfaces have to be assigned to a physical port. By default, LAN is assigned to port 0 and WAN is assigned to port 1. Assignments can be changed by going to Interfaces ‣ Assignments. This lists existing interfaces, with the interface name on the left and the physical port selected in the dropdown. New ones can be created here as well, using a non-occupied physical port.

When creating a new interfaces or changing an existing one (which can be done by clicking its name in the overview), the following options are available:

Option

Explanation

General configuration

Enable interface

Disable the interface without needing to remove its assignment altogether.

Prevent interface removal

Avoids accidentally removing an interface (has to be turned off and saved before an interface can be removed).

General configuration

Description

A short description for clarification, if the name does not suffice.

Block private networks

Block traffic claiming to come from private addresses. On WAN interfaces, this kind of traffic should not happen legitimately.

Block bogon networks

Block traffic claiming to come from invalid or reserved addresses (Martian packets). Note that this also includes multicast traffic using OSPF and RTMP.

IPv4 Configuration type

How to obtain the IPv4 address for this connection.

IPv6 Configuration type

How to obtain the IPv6 address for this connection.

MAC Address

Can be used to spoof the MAC address. Can usually be left blank (in which case it will use the actual MAC address of the hardware).

MTU

Maximum Transfer Unit.

MSS

Maximum Segment Size.

Speed and duplex

It is recommended to leave this on the default, unless you know what you are doing and the setting you pick matches the one on the physical port.

In addition to these settings, the following blocks will be enabled depending on what is configured under “IPv4 Configuration type” and “IPv6 Configuration type”.

For IPv4:

Option

Explanation

Static IPv4 configuration

IPv4 address

IPv4 Upstream Gateway

DHCP client configuration

Configuration Mode

Alias IPv4 address

Used as a fixed alias IPv4 address by the DHCP client.

Reject Leases From

Can be used to ignore DHCP leases from ISP-issued modems, for example.

Hostname

This value is sent as the DHCP client identifier and hostname when requesting a DHCP lease. Some ISPs may require this (for client identification).

Override MTU

An ISP may incorrectly set an MTU value which can cause intermittent network disruption. By default this value will be ignored. Unsetting this option will allow to apply the MTU supplied by the ISP instead.

PPP configuration

Service Provider

By selecting a country, provider and plan here, OPNsense can fill in the other fields for you. If your provider or plan not in the list, you have to set them manually.

Username

Password

Phone number

Access Point Name (APN)

Modem port

Advanced PPP

Will take you to the Point-to-Point device settings.

PPPoE configuration

Username

Password

Service name

Leave blank unless specified by provider.

Host-Uniq

See above.

Dial-on-demand

Only connect when traffic is sent over the interface

Idle timeout (seconds)

Advanced and MLPPP

Will take you to the Point-to-Point device settings.

PPTP/L2TP configuration

Username

Password

Local IP address

Remote IP address

Dial-on-demand

Only connect when traffic is sent over the interface

Idle timeout (seconds)

Advanced

Will take you to the Point-to-Point device settings.

For IPv6:

Option

Explanation

Static IPv6 configuration

IPv6 address

IPv6 Upstream Gateway

Use IPv4 connectivity

Set the IPv6 address on the IPv4 PPP connectivity link.

DHCPv6 client configuration

Configuration Mode

Setting this to “Advanced” will make the settings below “Use VLAN priority” visible.

Request only an IPv6 prefix

Only request an IPv6 prefix; do not request an IPv6 address.

Prefix delegation size

The delegated prefix length provided by the DHCPv6 server. Normally specified by the ISP.

Send IPv6 prefix hint

Send an IPv6 prefix hint to indicate the desired prefix size for delegation

Directly send SOLICIT

In case the ISP requires a SOLICIT message for authentication, select this option to prevent indefinite waiting for a router advertisement.

Prevent release

Do not send a release message on client exit to prevent the release of an allocated address or prefix on the server.

Enable debug

Enable debug mode for DHCPv6 client

Use IPv4 connectivity

Set the IPv6 address on the IPv4 PPP connectivity link.

Use VLAN priority

Certain ISPs may require that DHCPv6 requests are sent with a specific VLAN priority.

Interface Statement

Click the “i” to see what the four subfields do.

Identity Association

Prefix Interface

Authentication

Keyinfo

SLAAC configuration

Use IPv4 connectivity

Set the IPv6 address on the IPv4 PPP connectivity link.

6RD Rapid Deployment

6RD prefix

The 6RD IPv6 prefix assigned by your ISP. e.g. ‘2001:db8::/32’

6RD Border Relay

The 6RD IPv4 gateway address assigned by your ISP

6RD IPv4 Prefix length

The 6RD IPv4 prefix length. Normally specified by the ISP. A value of 0 means we embed the entire IPv4 address in the 6RD prefix.

6RD IPv4 Prefix address

The 6RD IPv4 prefix address. Optionally overrides the automatic detection.

Track IPv6 interface

IPv6 Interface

This selects the dynamic IPv6 WAN interface to track for configuration.

IPv6 Prefix ID

The delegated IPv6 prefix ID. This determines the configurable /64 network ID based on the dynamic IPv6 connection.

Manual Configuration

If this option is set, you will be able to manually set the DHCPv6 and Router Advertisments service for this interface. Use with care.

Mobile Networking

../_images/OPNsense_4G_new.png

OPNsense supports 3G and 4G (LTE) cellular modems as failsafe or primary WAN interface. Both USB and (mini)PCIe cards are supported.

Supported Devices

While all devices supported by HardenedBSD will likely function under OPNsense their configuration depends on a AT command string that can differ from device to device. To make thing easier some of these strings are part of a easy selectable profile.

Tested devices by the OPNsense team include:

  • Huawei ME909u-521 (device cuaUx.0)

  • Huawei E220 (device cuaUx.0)

  • Sierra Wireless MC7304 (device cuaUx.2) [as of OPNsense 16.7]

Note

If you have tested a cellular modem that is not on this list, but does work then please report it to the project so we can list it and inform others.

Configure Cellular modems

Setting up and configuring a cellular modem is easy, see: Configuring Cellular Modems

3G - 4G Cellular Failover

To setup Cellular Failover, just follow these two how-tos:

  1. Configuring Cellular Modems

  2. Multi WAN

Note

Treat the cellular connection the same as a normal WAN connection.