The interface settings screen will differ based on the type of interface being dealt with. In pfSense the real distinction between “WAN”, “LAN” and “OPT” interfaces is blurred as they are all capable of handling any role. For historical and ease-of-use purposes, the first two interfaces are WAN and LAN. Additional interfaces start at OPT1 and are numbered from there (OPT2, OPT3, … OPTn)
Interfaces can have their descriptive names changed, MAC address spoofed, and MTU adjusted. Any interface can be set for Static IP, DHCP, PPPoE, PPP, PPTP, or L2TP. The latter two are for ISP connections involving PPTP and L2TP directly. They are not intended to connect to remote VPNs.
For Static IP interfaces, the IP address and CIDR mask are manually entered.
If this will be a WAN-type interface, either select a gateway from the list or click add a new one to create a new gateway.
When creating a gateway, optionally check the box to select it as a Default Gateway, enter a Name, Gateway IP address, and a Description.
For DHCP interfaces, a DHCP hostname may be entered, and also optionally add an Alias IP address and subnet mask.
PPPoE and PPTP interfaces take a username and password, and optionally a service name, dial-on-demand setting, idle timeout, and optional periodic reset (PPPoE only).
All interfaces have the ability to use the Block Private Addresses and Block Bogon Networks options. These will block RFC 1918, RFC 4193, and unassigned networks, respectively.
Take care when activating this option. Never activate it on an interface with an address in RFC 1918 or RFC 4193 that should allow inbound traffic to the GUI or beyond, such as the interface from which the GUI is managed, or through which local clients would reach the Internet.
Wireless network interfaces also have several other options available, such as the SSID and encryption type (WPA, WPA2, etc).
Most wireless interfaces can operate in Access Point mode and allow clients to connect, but a few are limited to being used in Infrastructure mode, such as connecting to a wireless WAN or other local access point. See the articles in the 802.11 Wireless section for more information.
The MAC address field changes the MAC address used by the network card. This is usually only needed when replacing an existing device and the ARP table of connected devices cannot be controlled or easily changed.
In some cases, spoofing the MAC may require running the NIC in promiscuous mode. This is uncommon and is isolated to cases with certain network card chipsets, and certain cases when spoofing the MAC on VLAN interfaces.
In these cases, one option is to install the shellcmd package or add a command manually to run a command such as:
/sbin/ifconfig em0 promisc