pfSense Hardware Requirements

pfSense Hardware RequirementsBefore you set up your pfSense system, you probably want to consider pfSense hardware requirements. The two main factors that will determine your requirements are:

  • Throughput required
  • Features that will be used

If you require less than 10 Mbps of throughput, then even a Pentium I with a 100 MHz CPU will do. If you require greater throughput, the official pfSense website has the following guidelines (they assure us that the guidelines offer a bit of breathing room):

Summary of pfSense Hardware Requirements

pfSense Hardware Requirements
Throughput Minumum CPU Speed Minimum Interface
10-20 Mbps 266 MHz PCI
21-50 Mbps 500 MHz PCI
51-200 Mbps 1 GHz PCI
201-500 Mbps 2 GHz PCI-X or PCI-e
501+ Mbps 3 GHz PCI-X or PCI-e

Virtually all network cards are supported by pfSense, but not all network cards are created equal. Intel Pro 100/1000 NICs have solid driver support in FreeBSD. NICs such as the Realtek 8139, however, do not perform as well and may require slightly more overhead. Moreover, with some NICs, there are some things that may not work properly at all, such as VLANs or promiscuous mode required for bridging. Generally if you are buying NICs for a new deployment, Intel Pros are the most reliable.

In addition to these guidelines, pfSense’s hardware sizing guidance page mentions the following about pfSense features and how they may relate to pfSense hardware requirements:

  • VPN – Heavy use of any VPN services will increase CPU requirements. Encrypting and decrypting traffic is CPU intensive. A CPU’s encrypted throughput is roughly 20 percent of its unencrypted throughput. For example, a 266 MHz CPU will max out around 4 Mbps of IPsec throughput; a 500 MHz CPU can push 10-15 Mbps of IPSec; and relatively new server hardware deployments (Xeon 800 FSB) are pushing over 100 Mbps with plenty of capacity to spare. Encryption cards can, however, reduce CPU requirements. Check the FreeBSD hardware compatibility list (HCL) before making a purchase, but Soekris VPN-1401 seems to be well-supported. In addition, you may have better luck by switching protocols. OpenVPN, for example, requires less CPU usage than L2TP/IPSec. I am not sure how well PPTP competes with OpenVPN, but presumably it is less CPU intensive, if for no other reason than the fact that it only offers 128-bit encryption versus 256 bits for OpenVPN. As always, the most recent pfSense build will likely provide the best performance. The number of connections is not as significant as the overall throughput required.
  • Captive portal – While the primary concern is typically throughput, environments with hundreds of simultaneous captive portal users will require slightly more CPU power than otherwise, thus increasing the pfSense hardware requirements.
  • Large state tables – State table entries require about 1 KB of RAM each. The default state table, when full at 10,000 entries, takes up a little less than 10 MB RAM. For large environments requiring state stables with hundreds of thousands of connections, you will want to ensure adequate RAM is available.
  • Packages – Some of the packages require more RAM; Snort and ntop are two that should not be installed on a system with less than 512 MB RAM. Also, the Squid package is used for caching web content and requires extensive use of a hard disk with a large amount of storage. It is not for use with an embedded installation where writes to the compact flash card are kept to a minimum.

To show how these pfSense hardware requirements work in practice, let’s assume we want to set up a pfSense box for a small office. The office has a 50 Mbps net connection; we want to anticipate future use, but we don’t anticipate the office getting a connection faster than 100 Mbps in the forseable future. We also anticipate making use of VPNs for remote connections to the office, but we don’t plan on having more than a few VPN connections at any given time. Of the packages available, we opt to install Snort. From this information, we can determine our minimum hardware requirements:

  • 1 GHz CPU
  • 512 MB RAM (1 GB recommended)
  • Unencrypted throughput of 50 Mbps; unencrypted throughput of 10 Mbps
  • 100 Mbps network interface cards (1 Gbps recommended)

If we want to have a failover for the firewall, our requirements would include a second machine to be used as a failover. Keep in mind that the firewall’s throughput is only a bottleneck for traffic passing through it. Traffic to and from the Internet from the LAN and the DMZ meet that requirement, as does traffic between the LAN and the DMZ. Traffic between two systems on the LAN, however, or two systems on the DMZ would not be affected.
This is my take on minimum pfSense hardware requirements, but those of you who have experience in deploying pfSense firewalls may have a different take on this. If so, feel free to add your own comments on this subject.

External Links:

pfSense Hardware Requirements and Sizing Guidance at

VPN Protocol Comparison List – provides some guidance as to overhead for the different protocols

How to speed up IPSec, hardware encryption devices? at

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