pfSense Multi-WAN Configuration: Part Three

pfSense multi-WAN

Advanced Outbound NAT settings in pfSense 2.2.4.

Some multi-WAN configurations require special workarounds because of limitations in pfSense. This article covers those special cases.

Because of the way pfSense distributes traffic over multiple Internet connections using the same gateway IP, you will need to insert a NAT device between all but one of those connections. This is not an elegant solution, but it is a workable one.

pfSense can only accommodate one PPPoE or PPTP WAN connection. Therefore, OPT WAN interfaces cannot use PPPoE or PPTP WAN types. If you need to use PPPoE or PPTP, the best workaround is to use them on your modem or another firewall. Most DSL modems can handle PPPoE and either directly assign your public IP to pfSense or give it a private IP and provide NAT. Public IP passthrough is possible on many modems and is the preferred means of doing this.

pfSense Multi-WAN: NAT Rules

The default NAT rules generated by pfSense will translate any traffic leaving the WAN or an OPT WAN interface to that interface’s IP address. In a default two interface LAN and WAN configuration, pfSense will NAT all traffic leaving the WAN interface to the WAN IP address. The addition of OPT WAN interfaces extends this to NAT any traffic leaving an OPT WAN interface’s IP address. This is the default behavior and is all handled automatically unless Advanced Outbound NAT is enabled. The policy routing rules direct the traffic to the wAN interface used, and the outbound and 1:1 NAT rules specify how the traffic will be translated. If you require Advanced Outbound NAT with multi-WAN, you will need to configure NAT rules for all your WAN interfaces.

When using port forwarding with a multiple WAN setup, keep in mind that each port forward applies to a single WAN interface. A given port can be opened on multiple WAN interfaces by using multiple port forward entries, one per WAN itnerface. The easiest way to accomplish this is to add the port forward on the first WAN connect, then click the plus button to the right of that entry to add another port forward based on that one. Change the interface to the desired WAN interface, and press the Save button.

1:1 NAT entries are specific to a single WAN interface. Internal systems can be configured with a 1:1 NAT entry on each WAN interface, or a 1:1 entry on one or more WAN interfaces and use the default outbound NAT on others. Where 1:1 entries are configured, they always override any other Outbound NAT configuration for the specific interface where the 1:1 entry is configured.

External Links:

Network Load Balancing on Wikipedia

pfSense VPN: Part Three (PPTP)

pfSense VPN

VPN PPTP configuration page in the pfSense GUI.

In the previous two articles on pfSense VPN, I covered how to configure a VPN tunnel using IPsec and also the L2TP and OpenVPN protocols. In this article, I will cover how to set up a VPN tunnel using PPTP.


pfSense VPN: PPTP

First, browse to VPN -> PPTP. You should be at the “Configuration” tab. You will see the following warning message:

PPTP is no longer considered a secure VPN technology because it relies upon MS-CHAPv2 which has been compromised. If you continue to use PPTP be aware that intercepted traffic can be decrypted by a third party, so it should be considered unencrypted. We advise migrating to another VPN type such as OpenVPN or IPsec.

Click on the “Enable PPTP server” radio button. At “No. PPTP users“, select the number of PPTP users. At “Server address“, etner an unused IP address. PfSense’s PPTP service will listen on this address. In the next box, Enter the start of the “Remote address range” for clients that connect (it must be large enough for the number of users specified at “No. PPTP users“). Check the “Require 128-bit encryption” checkbox just above the “Save” button. Click on “Save” to save the configuration.

pfSense VPN

Users tab in the VPN PPTP setup in pfSense.

Now select the “Users” tab and hit the “plus” button to add a user. Specify a “Username” and “Password” and an “IP address” if you want the user to be assigned a specific IP address. Click on “Save” to save changes, and then click on “Apply changes” if necessary.

Now it is necessary to set up a firewall rule to allow PPTP VPN traffic. Browse to Firewall -> Rules. Select the “PPTP VPN” tab. At “Destination“, set it to “LAN subnet“. Set the “Destination port range” to “any“, and at “Description“, enter a description if desired. Then press “Save” to save the changes and press “Apply changes” if necessary.


Now, your pfSense router will be configured to use VPN with PPTP. Moreover, PPTP is natively supported by Windows, Linux and MacOS, so you should be able to easily connect to your VPN tunnel from any of those platforms.

External Links:

PPTP VPN at doc.pfsense.org

 

pfSense VPN: Part One

pfSense VPN

Configuring an IPsec VPN tunnel in pfSense 2.0.

Virtual Private Networking (VPN) extends a private network across a public network, such as the Internet. It enables a computer to send and receive data across shared or public networks as if it were directly connected to the private network, while benefiting from the functionality, security and management policies of the private network, and is accomplished by establishing a virtual point-to-point connection with another computer. This is done through dedicated connections, encryption, or a combination of the two. Most router/firewalls support VPN, and this article describes some of the pfSense VPN options.


There are a variety of VPN services available, and pfSense has four of the most popular implementations built right in: IPsec, L2TP, OpenVPN, and PPTP. OpenVPN is emerging as the standard VPN protocol, but OpenVPN support is not built into Windows – you’ll have to download the client software. IPsec is also a popular VPN implementation. PPTP and L2TP, on the other hand, are losing ground to OpenVPN, but are still popular and are supported by most major operating systems.

pfSense VPN: IPsec

pfSense VPN

Setting up a firewall rule to allow IPsec traffic to the LAN.

In many cases, IPsec is the preferred method for network-to-network connections. IPsec (Internet Protocol Security) is a technology protocol suite for securing Internet Protocol (IP) communications by authenticating and/or encrypting each IP packet of a communication session. IPsec also includes protocols for establishing mutual authentication between agents at the beginning of the session and negotiation of cryptographic keys to be used during the session. Setting up an IPsec connection in pfSense is easy. Browse to VPN -> IPsec. If the “Tunnels” tab is not already selected, select it. Click the “Plus” button to create an IPsec tunnel. Leave “Disable this phase 1 entry” unchecked and keep the interface as “WAN“. At “Remote Gateway“, enter the public IP address or host name of the remote gateway. At “Pre-Shared Key“, input your pre-shared key string. Now, click on “Save” to save the changes, click on “Enable IPsec“, and click on the “Save” button again. Click on “Apply changes” if necessary.


In order for IPsec traffic to pass through to the LAN, we need to create a new rule. Browse to Firewall -> Rules and select the IPsec tab. Click on the “Plus” button to add a new firewall rule. At “Destination“, set the destination to the LAN subnet, and at “Destination port“, set the destination port to “any“. Add a description at “Description” if you want, and click on “Save” to save changes. Click on “Apply changes” if necessary. This completes the set up of a pfSense VPN tunnel with IPsec.

In the next article, I will cover using VPN with the L2TP and OpenVPN protocols. Part three will cover the PPTP protocol.

External Links:

Setting up an IPsec VPN Link at doc.pfsense.org

pfSense Setup: Part Three (WAN and LAN Settings)

In pfSense Setup: Part Two,  I covered General Settings within the pfSense web GUI. In this part, I cover configuring the WAN and LAN interfaces. There are a number of different options here; fortunately, pfSense makes the job easy on us by creating reasonable defaults. From the pfSense web GUI menu, go to Interfaces -> WAN.

pfSense Setup: WAN Interface Settings

WAN

The WAN settings page in the pfSense web GUI.

The WAN interface provides your connection to the Internet. To access the WAN, you will need a properly-configured WAN interface and an Internet connection. Typically your Internet connection will be through a cable modem provided by your Internet service provider (ISP), but pfSense will support other connection methods as well.

To configure the WAN interface, browse to Interfaces | WAN. Under “General Configuration”, check Enable Interface. You can change the description of the interface (Description).

The next item is “Type”. Here you can choose the interface type. “Static” requires you to type in the WAN interface IP address. “DHCP” gets the IP address from the ISP’s DHCP server, and is probably what you want to select. “PPP” stands for Point-to-Point Protocol, a protocol used for dialup modem connects as well as T-carrier, E-carrier connections, SONET and SDH connections and higher bitrate optical connections. “PPPoE” stands for Point-to-Point Protocol over Ethernet and is used by a number of DSL providers. “PPTP” stands for Point-to-Point Tunneling Protocol and is a method for implementing virtual private networks (VPNs); unless your WAN interface is a VPN you won’t want to choose this option. “L2TP” stands for Layer 2 Tunneling Protocol, a tunneling protocol also used with VPNs.

The next option is MAC address. Typing in a MAC address here allows you to “spoof” a MAC address. The DHCP servers of ISPs assign IP addresses based on MAC addresses. But they have no way of verifying a MAC address, so by typing a different MAC address, you can “force” your ISP’s DHCP server to give you another IP address. Unless you want to spoof your MAC address, you can leave this field blank. MTU stands for maximum transmission unit. Larger MTUs bring greater efficiency but also greater latency. This should probably be left unchanged. MSS stands for maximum segment size, and specifies the largest amount of data pfSense can receive in a single TCP segment. This also should likely be left unchanged.


The next section is different depending on what you selected for the interface type. If you selected “DHCP”, the options will be “Hostname” and “Alias IP Address”. Hostname can be left blank unless your ISP requires it for client identification, and Alias IP address can also be left blank unless the ISP’s DHCP client needs an alias IP address.

The next section is “Private Networks”. Checking “Block private networks” ensures that 10.x.x.x, 172.16.x.x, and 192.168.x.x addresses, as well as loopback addresses (127.x.x.x) are non-routable. This should be left checked under most circumstances. “Block bogon networks” blocks traffic from IP addresses either reserved or not yet assigned by IANA. This should be left checked as well, for obvious reasons.

Save the options and move on to Interfaces -> LAN.

pfSense Setup: LAN Interface Settings

WAN

The LAN settings page in the pfSense web GUI.

Under “General Configuration”, “Enable Interface” should be checked, since unchecking it will prevent the local network from connecting to the router. “Description” allows you to type in a description of the interface.

“Type” allows you to choose an interface type. See the section on WAN settings for an explanation of each of the options. “MAC address” allows you to type in a different MAC address in order to do MAC address spoofing. Again, see the section on WAN interface settings for a more detailed explanation. “MTU” and “MSS” are also explained under WAN settings. “Speed and duplex” allows you to explicitly set speed and duplex mode for the interface; pfSense should autodetect this, so this option should be left unchanged.

If you selected “Static” for the interface, there should be a “Static IP Configuration” section with two options: “IP address” and “Gateway”. With “IP address”, you can change the IP address of the LAN interface (it defaults to 192.168.1.1).

The next section is “Private networks”. The two options are “Block private networks” and “Block bogon networks”. See the section on configuring the WAN interface for detailed explanations of these options.

That does it for WAN and LAN settings. In pfSense Setup: Part Four, I will take a look at setting up an optional interface.


The Rest of the Guide:

Part One (installation from LiveCD)

Part Two (configuration using the web GUI)

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