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Feature: Networking

Protect your network with pfSense firewall/router

By Cory Buford on October 03, 2008 (9:00:00 AM)

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pfSense is a free, powerful firewall and routing application that allows you to expand your network without compromising its security. Started in 2004 as a child project of m0n0wall -- a security project that focuses on embedded systems -- pfSense has had more than 1 million downloads and is used to protect networks of all sizes, from home offices to large enterprises. pfSense has an active development community, and more features are being added in each release to further improve its flexibility, scalability, and, of course, security.

The latest version, 1.2, includes features that you normally see on commercial firewall or router devices, including a Web-based GUI for easy management. While it has impressive features for a free firewall/router, it also suffers from some limitations.

As a firewall, pfSense supports filtering by source and destination address, by source and destination port, and by IP address. For example, if I use source address filtering and set the IP address to be monitored to be the subnet of the internal network, any traffic or request that originated from that address will be analyzed and filtered depending on the firewall rules. If I use destination filtering, the firewall will monitor the IP address that the traffic is going to, and if the destination address is within the firewall rules, then the appropriate action will be applied.

One of the best firewall features is its passive operating system fingerprinting (p0f) capability, which passively detects the connection's OS and allows the firewall to block connections based on the connecting node's OS. It also supports policy routing, and can operate in bridge or transparent mode, allowing you to just drop pfSense in between network devices without requiring additional configuration. pfSense provides network address translation (NAT) and port forwarding, but there are limitations with Point-to-Point Tunneling Protocol (PPTP), Generic Routing Encapsulation (GRE), and Session Initiation Protocol (SIP) when using NAT.

pfSense is based on FreeBSD, and FreeBSD's Common Address Redundancy Protocol (CARP) provides redundancy by allowing administrators to group two or more firewalls into a failover group. Because it supports multiple wide area network (WAN) connections, it can perform outbound and inbound load balancing. The only limitation with this is that it can only do equal distribution of traffic between WAN connections, and you cannot prioritize specific traffic to be passed on a chosen connection.

pfSense supports virtual private networking (VPN) using Internet Protocol Security (IPSec), OpenVPN, or PPTP. Since there are some limitations with NAT, IPSec VPN is limited when connections are through NAT, resulting in a lack of support for remote or mobile VPN clients. The software also lacks advanced IPSec features like NAT Traversal in the Internet key exchange (IKE), known as NAT-T, and Xauth. You could choose OpenVPN to circumvent some of these limitations, but it too has some limitations, though the development team has promised to resolve these limitations in its next release. The pfSense site details the features and limitations.

Installing pfSense

To get started, download pfSense, and choose between an embedded package or a live CD ISO package. Choose the embedded package only if you're going to use it on a compact network device that utilizes flash technology for storage. Most people should choose the live CD ISO for a normal PC. To run pfSense correctly, you need a box with at minimum a 100MHz CPU with 128MB of RAM and at least two network interface cards (NIC), one each for the WAN and LAN interfaces. This minimum requirement is good for a throughput of less than 10Mbps. As your network throughput and feature use increases, so too do the pfSense requirements. Check pfSense's selection and sizing page to learn the most appropriate specifications for your requirements.

I downloaded the 60MB live CD ISO and burned it to a disc. Upon booting the live CD, you're presented with several options. If this is your initial installation of pfSense, select the default option. The initial boot process consists of setting the VLAN and choosing the interfaces for LAN and WAN. You can automatically detect the interface settings, but make sure the interfaces are already connected. If they're not, you'll have to enter the interface names manually. For my setup, pfSense chose le0 for my LAN interface and le1 for the WAN.

After the initial configuration, the boot process continues until you reach pfSense's console, which is a simple menu that lets you configure interface settings, activate Web configuration and other services, reset the configuration to factory defaults, and install pfSense to the hard disk. pfSense automatically assigns an IP address for the LAN interface, but I wanted to use a specific address, so I had to change the LAN IP address so that the new IP address would be used during the hard disk installation. I then proceeded to the straightforward hard disk installation.

You must format and create a disk partition before you install pfSense. If you choose the recommended partition, pfSense will create that for you. However, you still have the option to create you own partition layout. For my setup, I chose the default partition recommended by the installation. During the installation, pfSense asks you what type of system you want to install it on. You can choose a normal station (a uniprocessor or multiprocessor), a headless station without any console or keyboard, or an embedded system. I chose a uniprocessor system. After installation, restart your machine and, using the LAN IP address configure option, access the Web configuration interface.

Using pfSense

pfSense's configuration is not too different from that of any network firewall and router that uses Web-based configuration. After you log in with the default username and password, you can configure the firewall's interfaces and rules. For secure Web-based management, change the default password and set the session type to HTTPS on the general setup properties. Here you can also set the DNS settings of the firewall.

LAN configuration is straightforward. If you have not already done so before installing, you only need to set up the IP address. In the WAN interface, you can choose among various connections like Static, Dynamic Host Configuration Protocol (DHCP), Point-to-Point Protocol over Ethernet (PPPoE), and BigPond cable. Choose the appropriate connection as configured by your ISP.

Once you've configured the interfaces properly you can set up some firewall policies. As with any firewall device, setting up a firewall policy requires you to select an interface (WAN or LAN), source address and port, destination address and port, protocols and services, and pass, block, or reject action types. Block drops packets completely, while reject returns an "unreachable" response to the host initiating the connection. For security, it's better to block than to reject. Under Firewall you can also configure NAT settings if you need to use port forwarding for services or configure static NAT (1:1) for specific hosts. NAT's default setting for outbound connections is automatic/dynamic, but you can change that to manual if necessary. I tested some of the firewall rules I created, such as those for blocking FTP access to outside networks, and pfSense blocked the service successfully.

I also tested the VPN features of pfSense. It supports IPSec, OpenVPN, and PPTP. If you need a fast VPN connection and have less bandwidth available than is required by SSL VPN connections with good security, you can choose IPSec VPN. If you have handled IPSec VPN configuration in the past, you'll find that configuring IPSec in VPN is a breeze and can be accomplished in just a few minutes. Make sure that the parameters for the algorithms in use are the same for both ends of the tunnel. Also note the limitations of IPSec VPN on the pfSense Developers Wiki. For simple IPSec configuration, pfSense's limitations can be tolerated, and it works well for site-to-site setups that I've tested. However, for serious applications involving mobile clients and authentication, you'll find the IPSec configuration in pfSense lacking.

You can use OpenVPN to circumvent IPSec's limitations. Aside from that, OpenVPN can prove to be more secure, since it uses SSL. The only downside is that it requires more overhead due to the SSL, which also means that it eats more bandwidth than IPSec.

If you have VPN clients still using PPTP dial-up connections, pfSense fully supports PPTP as well.

Other features of pfSense, like its multiple WAN connection capability and its load balancing, are worth trying. You can also set up a "captive portal," which requires every user who accesses the network to authenticate himself through a local database or Remote Authentication Dial-In User Service (RADIUS) before being allowed in. For users who need to access your network using PPPoE, a PPPoE server is available, and authentication may be based locally or via RADIUS.

Monitoring and logging events in pfTools is easy. It features real-time RRDtool graphs, visually displaying every operational process in your box, including traffic and system processes. Unlike some commercial network devices, the logs are well organized and can be located easily. This, along with included diagnostic tools like the traditional traceroute and a packet sniffer, proves to be helpful for efficient troubleshooting.

Does it make sense to try pfSense?

Although some features need improvement, pfSense's capabilities as a firewall and router make it good enough to be put on an office network. It's easy to manage and offers features that you see on commercial products. However, since some features commonly used in large enterprise networks are limited, I would not recommend it for such use. With its active development community, the project should resolve those issues as new features are added.

With its multiple WAN capability and load balancing, you can add pfSense to the growing list of low-cost, or free, network firewall/router solutions.

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on Protect your network with pfSense firewall/router

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Protect your network with pfSense firewall/router

Posted by: Anonymous [ip: 212.44.62.230] on October 03, 2008 05:16 PM
we've got six pairs (clusters) of firewalls in live use using pfsense, and they work really well. heartily recommend trying this out.

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Re: Protect your network with pfSense firewall/router

Posted by: Anonymous [ip: 82.80.140.50] on October 03, 2008 07:34 PM
have you measured the traffic passing through? what is the expected bandwidth? can i reach 1Gb/sec with a software solution?

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Re(1): Protect your network with pfSense firewall/router

Posted by: Anonymous [ip: 68.238.158.178] on October 03, 2008 08:18 PM
With fast enough hardware, you could do it. First, a 64 Bit system. Some motherboards come with a Gigabit chip on it that can run full 1 gig (PCI Express) and has TCP offloading. Some motherboards come with 2 such chips. If not - get a PCI Express gb card that can off load TCP. 2 gig of ram min.

If multicore is taken advantage of by pfSense, then defenately get a quad core - 2.4GHz..

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Re(1): Protect your network with pfSense firewall/router

Posted by: Anonymous [ip: 24.249.6.134] on October 05, 2008 02:28 PM
You should look at the spec's of a hardware or firewall appliance. A hardware solution is nothing more than a self contained CPU, memory, and switch with the software contained in ROM for bootup. In reality, it is as much a software solution as running software on a PC - literally. They do not have anywhere near the power of a full blown PC. In other words, a hardware solution has nothing speacial. It relies on software just as any other device that uses a cpu. Software based solutions running on a PC are only as "weak or strong" as the CPU doing the processing.

So if you use a modern CPU and GB ethernet cards, you can do just as much or more than with a overpriced firewall appliance. In fact, I use Linux's iptables for my firewalls . I'm not limited to two interfaces.

If you are thinking that a hardware or firewall appliance is anything other than a "software" based solution, think again. When you turn them on they bootup just like a pc and load software, their os as well as app, just like a PC.

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Protect your network with pfSense firewall/router

Posted by: Anonymous [ip: 82.75.123.184] on October 06, 2008 12:11 AM
I don't know about pfSense/FreeBSD, but I know in OpenBSD (where pf comes from) TCP-offloading isn't used.

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Re: Protect your network with pfSense firewall/router

Posted by: Anonymous [ip: 75.138.105.255] on October 07, 2008 03:52 AM
I've got a redundant pair for our Production firewalls. pFsense uses CARP for vip redundancy all rules automatically sync between firewalls (unless you specify otherwise).
Each firewall has 4 Nics/zones plus one for firewall sync/heartbeat.
Between our corporate network (Gb) and our production (Gb) I do notice some minor drop in thru-put ~10% but we are talking two firewall hops.

Back in the day I've installed and managed a number of different firewalls, Gauntlet, Checkpoint, Raptor, Cisco PIX, as well as linux iptables. While Idon't think most corporations will replace their $30K firewall solutions w/ pfSense anytime soon. Most businesess w/o quite that much money to throw around should consider this slightly less polished solution and a ice donaion to keep the effort moving forward.

Caveat: I found the ftp support not to my liking so I compiled jftpgw on a freebsd box and installed it along w/ the pfSense supplied djbDNS server package. I use tcpserver to keep jftpge running.

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Protect your network with pfSense firewall/router

Posted by: Lucien Raven on October 07, 2008 02:17 PM
I´m looking for solutions to improve our company´s firewalls which are pure iptables in a Linux-HA configuration. pfSense is really an interesting option and will be giving a try.

As a follow-up to the article, take a look at http://blog.pfsense.org/?p=238 , pfSense team addressed the OpenVPN and IPsec issues pointed in this very article and released version 1.3-alpha snapshots for testing.

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Just so you know, pfSense 1.3-ALPHA is definately alpha

Posted by: Anonymous [ip: 67.164.117.76] on October 08, 2008 09:57 PM
...I mean, *really* alpha. The update this morning broke NAT... can't get much more fundamental than that. :) Despite that, it's shaping up to be a robust release.

As for TCP offloading (inlcuding 802.1Q), FreeBSD does support it, but on a driver-by-driver basis. pfSense does need a *lot* more cycles as compared to Linux/IPTables or FreeBSD/IPFW, but mainly because it's handling each packet much more heavily... for better or worse. If you're looking for an open-source embedded-style firewall that can run on very low specifications, m0n0wall or a Linux-based option might be a better choice. If you have the hardware to throw at it though, pfSense has some very competitive features. There's a reason the authors went with PF, even in light of it's CPU-hungry nature.

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dual carp & ipsec from europe to asia

Posted by: Anonymous [ip: 82.235.179.84] on October 10, 2008 01:31 PM
I have a setup involving PCENGINE Alix motherboards, two nodes CARP linked in france, two others CARP linked in thailand.
I run an ipsec link between the two.
I can filter all traffic but smb shares.
Sure 1.2 has a few issues, specially when it comes to wireless, but 1.2.1, 1.3, and the general move to RELENG_7 will improve many many things.
And it's free.

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Protect your network with pfSense firewall/router

Posted by: Anonymous [ip: 202.61.227.13] on October 22, 2008 03:04 AM
How does it compare to monowall and smoothwall?

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