We will go over how to set up a simple, easy-to-configure firewall that denies most traffic. When setting up a new FreeBSD server, there are a number of optional.
With 3mbit (2 x t1) it may get to 4% CPU usage if you’re lucky. I’ve had a p3/650 with 192 meg ram running OpenBSD 3. 6 and doing bridging firewalling using PF for a few years now. As long as you don’t run the extra stuff like snort and squid, a MUCH lower-end machine will work great.
A step-by-step guide for setting ipfw firewall under FreeBSD operating systems. FreeBSD Setting up Firewall using IPFW.
To configure the system to enable IPF at boot time, add the following entries to /etc/rc. These entries will also enable logging and default pass all. To change the default policy to block all without compiling a custom kernel, remember to add a block all rule at the end of the ruleset.
This is not the case. Even more overkill than an Athlon 64. Nowdays 256MB of RAM is marginally more expensive (sometimes cheaper) than smaller capacities due to production, ROI, and storage costs. They are often referred to as DIMM slots. ATA comes in ATA66, ATA100, ATA133, and ATA166. If you don’t have a fan, be sure you have a decent passive-heatsink, acceptable ambient air temperature, and adequate airflow in and around the case. » Drive interfaces – These are where your drives connect to your motherboard. This tutorial will only cover 10BaseT to 1000BaseTX NICs. » Form factor – This determines what kind of case you can use. » AMD Duron – Found in Socket A only. Hard drive capacities greater than 1GB should be plenty. If your computer turns off randomly, it is your hardware protecting itself from the lack of power. Make sure you have enough of the appropriate connections to power all of your devices. Physically building a computer from scratch is much easier than most people think. Another interface typically found in server environments is SCSI. A 300W PSU is more than enough for the minimal PC that we’ll be building. NIC
In our case, your NICs (Network Interface Cards) will be a vital component to the functionality of your PC. On newer drives and controllers you will see the label Serial-ATA or SATA. In fact, it would be possible to build this project without a harddrive altogether. Although, I’d be happy to take an Athlon 64 FX-60 off of someone’s hands 😛
» AMD Opteron – Socket 940. Often times you will see a motherboard that says it supports ATA133. Rarely are newer technologies backwards compatible with older ones, but ocasionally you’ll find that a firmware update will allow this. Often times a socket will be named after it’s pincount. Keyboards are the same. My suggestion would be to find a compatible motherboard and processor, then find the rest of your parts based on the capabilities of your motherboard. » Backpanel – This is the collection of plugs located at the back of the motherboard. It should be warm, but not hot. You will often see drives labeled ATA100 or ATA133. 8GHz Northwood – Found in Slot 1, Socket 370, 423, and 478 varieties. PSU
If the CPU is the brains of your computer, the PSU is the heart. These will work if your motherboard has the appropriate (SATA150 or SATAII/300) headers. Afterwards, you can unplug these. This hardware is cheap, and it’s a good learning experience. A fast system relies equally on the speed of all the devices. SATA150 (aka SATA-I or just SATA) is often compatible with SATA300 (aka SATA-II or SATA with NCQ) motherboards. You will almost always find your keyboard, mouse, parallel, and serial connectors here. You will experience random, unexplained problems if you skimp on the power supply. Every computer must have the following parts:
» Processor (obviously)
» Physical drives – optical and/or hard)
» Input/output devices – NICs, keyboards, mice, monitors, etc. One of the most common problems with building computers is a weak/unstable PSU. » AMD Athlon XP – Found in Socket A. Sometimes you will see the pincount mentioned in the name or description. In most cases, if the processor and socket have the same pincount, they are compatible. If it doesn’t, you can probably find conversion wires to make it fit for a few bucks at your local computer store. Larger capacities will help speed up your compiling processes. Be careful though, this is not always the case. ), ATX (most common), Mini-ATX (small versions of ATX), Micro-ATX (even smaller), Mini-/Micro-/Pico-/Nano- ITX (tiny. If you plan on using SATA, you will most likely need a different power connector; although, Western Digital usually places both the legacy 4-pin molex power connector and the new Serial-ATA connector (DON’T USE BOTH SIMULTANEOUSLY. Drives
ATA IDE drives are still the most common, but are being phased out by the faster and more efficient Serial ATA. Cooler running processors also last longer. Just check the backpanel of the motherboard to find out. These are being replaced by Serial-ATA due to cost. After the initial build, touch your processor from time to time to make sure that it’s cooling. Because most people don’t have internet connections higher than 10Mbps, the slower speed is acceptable here. There are adapters to convert most of these to the correct plug. ATA comes in ATA66, ATA100, ATA133, and ATA166. Phase-change cooling and TECs are MASSIVE overkill. Older processors are more stable, and therefore popular in the overclocking community. If you don’t, you can either remove some fans (BUT NOT THE CPU FAN. Make sure it supports your motherboard’s form factor. ), or find/purchase some 4-pin molex to 3-pin fan header conversion wires or 3-pin Y-splitters. » RAM slots – These are where your RAM goes. If the motherboard supports ATA133, it usually supports the slower ATA100 and ATA66 specifications. I’m running an Athlon 64 3700 San Diego in my gaming rig, so you can see how these are MAJOR overkill. Because you will not need a monitor, keyboard, or mouse after the initial installation process, it is possible to store the firewall virtually anywhere. » Intel Celeron 500A to 2. The later will not be covered here. Mice are either PS2 (no, not that one), USB, or the older ADB and RS232. » Intel Pentium 4 – Socket 423, 478, and T. Monitors come in VGA and DVI varieties (DVI being digital and newer). If you are not using a relatively new (1 year or younger) hard drive, it is wise to perform a diagnostics test before installing your system. Unplug and discharge it first. Newer processors are more succeptible to thermal damage due to tighter tolerances and electron-migration. Due to that large variety of physical connectors, it’s pretty hard to damage hardware by placing it in an incorrect slot. Add 100MB to that if you plan on using a desktop environment. Tiny cases might have cooling problems if they are placed in areas with poor circulation. 100Mbps ethernet (100BaseT) is much more common than 10BaseT(X) and perfectly acceptable, although it is unlikely that you will see any performance gain from using it. Make sure you nave enough ethernet cable also. Many boards also have VGA/S-Video, LAN, USB, Firewire, and/or audio jacks here also. ) Make sure that your NIC and video card each have a slot of their own (although it is possible to run this without a videocard). Larger cases are easier to use because you have more room for wires and connectors. If you can, try to make sure your NIC supports full-duplex to avoid collisions. SATA150 (aka SATA-I or just SATA) is often compatible with SATA300 (aka SATA-II or SATA with NCQ) motherboards. Because of their moving parts, hard drives are more prone to failure than the rest of your components. If you have to force something into a slot, you’re doing something wrong; otherwise, don’t worry about frying the component. Make sure you have enough to accomidate all of your fans. The hardest part about building a computer from scratch is finding the right parts. A TV can also be used if your motherboard and the TV both have S-Video connections and there is an S-Video driver for FreeBSD. Often times you’ll find one (or even two) NICs integrated into your motherboard. SATA is major overkill for a simple gateway/firewall because it will VERY rarely be used. I wouldn’t ming a TEC + Watercooling kit though 😛
I think that about covers the hardware, but here are a few things to keep in mind:
» Larger RAM capacities speed up your compilation process. » Intel Celeron D – Found in Socket 478 and T. Optical drives are what you’ll use to install the operating system. » Intel Pentium III – Found in Slot 1 and Socket 370 varieties. This is another place to be careful. » If you plan on placing this gateway firewall in a small location, make sure the case is small enough. RAM
Pretty much any RAM will work as long as it’s atleast as new as PC100 and is compatible with your motherboard. People are ingrained with the impression that a fast processor makes for a fast computer. The numbers are associated with theoretical maximum transfer rates. Though geared towards server environments, this processor is about as much overkill as you can find (expensive too). Form factors include AT (obsolete), Enhanced/Extended ATX (big boards. It may save you some headaches later. If your arm jerks in reflex to touching it, it’s too hot. Full duplex is denoted by an “X” on the end of the media type (eg. A motherboard with a fast chipset and high front-side bus (FSB) is just as important as a fast processor. Sometimes these have proprietary components that are not supported by FreeBSD drivers. Monitor, keyboard, and mouse
You should be familiar with these already. You will need two of these, one for the WAN side, and one for the LAN side. If you have to modify your PSU, take appropriate precautions. Make sure that your motherboard’s socket is compatible with your processor. If your PSU doesn’t fit in your case, you can modify the case to accomidate it. » Fan headers – These are where your CPU and case fans plugin. Depending on your hardware, you may need something as powerful as 300W. Due to the nearly inifinite variety, I will simply mention the most important features to consider. A decent capacity is but 128MB. » Intel Itanium – Found in PAC611. Wouldn’t you rather make mistakes now than when you build a multi-thousand dollar gaming rig. One of the most common signs of an underpowered computer is random shutdowns. You can use memtest to test your RAM prior to installing FreeBSD. Make sure your motherboard supports an ATA standard greater-than or equal to the one used by your harddrive. FreeBSD can be installed from CD ISOs or a single DVD ISO. 100MB is the absolute minimum, but 250MB is recommended. We will only need a keyboard and monitor for the initial setup process. If you need a Serial-ATA power connector, don’t worry, there’s conversion wires for those too. » AMD Athlon 64 – Socket 754 and 939. Be sure to double check. To give you an idea of how much is TOO much for this project, I use a 650W powersupply in my gaming rig; however, a more powerful PSU will not harm your system. » AMD Athlon 64 FX – Socket 939 and 940. » AMD Athlon MP – Found in Socket A. Overkill
» Intel Xeon – Socket 603, and 604. Then again, you may only need 100W. These are just re-labelled Athlon XPs. » Case (although it’s fun to leave this part out and mount the mobo on your wall)
» Cooling unit – Heatsink and/or fan (aka HSF), watercooling/phase-change cooling (not practical here, but fun regardless)
Often times, when building a computer, people put most of their money here. Your NICs will need to support atleast 10Mbps 10BaseT, but anything faster will work. Any of these will work, but be careful of Mini-/Micro-/Nano-/Pico- ATX/ITX boards. » Socket/Slot – This is where your CPU will live. Come in dual-core also. RAM is the other vital component in a fast system. For our system, the speed of all of these is a minor concern, as we are more concerned with the cost-effectiveness. I have mine in my closet. » AMD Sempron – Found in Socket A and 754. I’d be happy to take an EPIA N Nano-ITX off of someone’s hands also. Cooling
Be sure you have both a heatsink and fan. » Power interfaces – This is where your PSU connects to your motherboard. » Your NIC should support atleast 10Mbps ethernet (aka 10BaseT). Watercooling can bring your CPU temperatures close to ambient air temperature, but is overkill here. Serial ATA has the same considerations. They can drop your temperatures far below freezing where condensation becomes an issue. » AMD Athlon K7/K75/Thunderbird – Found in Slot A and Socket A. Paralell ATA (aka ATA, PATA, IDE, EIDE) drives are still the most common, but are being phased out by the faster and more efficient Serial ATA (SATA). Almost any drive will work for this as long as it is compatible with your motherboard. The most common are ISA (slowest and only found in industrial motherboards nowdays), PCI (slowest of all in common use, used for pretty much any kind of add-on card), AGP 1x/2x/4x/8x (common; almost always used by videocards; being phased out by PCI Express), PCI Express (fastest of all slots; typically used for videocards), PCI-X (not to be confused with PCI Express; can be (almost) as fast as PCI Express; comes in speeds such as 1x, 4x, 8x, etc. Make sure your PSU will plugin to your motherboard. I’m familiar with 20-pin and 24-pin connectors, as well as Intel/AMD 4-pin headers. The slots that I’m familiar with support SDRAM (PC100, PC133), DDR SDRAM and DDR2 SDRAM (In varietes from PC1700 to PC8500), and RAMBUS (rare, pricey RAM that was ahead of it’s time; only runs in pairs). » Input/output interfaces – These are where add-on cards go. » Your hard drive and optical drive should most likely be ATA IDE drives. » Your PSU (Power Supply Unit) should be able to supply enough STABLE power to all of your devices simultaneously. Motherboard
This is perhaps the hardest part to pick out, and also the most important. It can also be installed from a USB drive (if it’s large enough and your motherboard supports booting from USB) or the network.
Conf statement firewall_enable=”YES” is used. I'm new to FreeBSD and am trying to configure the firewall using IPFW. Module when the rc.
The from keyword must be followed by the source address or a keyword that represents the source address. An address can be represented by any, me (any address configured on an interface on this system), me6, (any IPv6 address configured on an interface on this system), or table followed by the number of a lookup table which contains a list of addresses. For example, 1. When specifying an IP address, it can be optionally followed by its CIDR mask or subnet mask. 4/25 or 1.
It is customary to duplicate the “ipfw default deny everything ” rule with the log keyword included as the last rule in the ruleset. The firewall administrator decides which rules in the ruleset will be logged, and adds the log keyword to those rules. Even with the logging facility enabled, IPFW will not generate any rule logging on its own. Normally only deny rules are logged. This way, it is possible to see all the packets that did not match any of the rules in the ruleset.
Several keywords can be added after keep state. Refer to ipf (5) for the list of available options and their descriptions. If used, these keywords set various options that control stateful filtering, such as setting connection limits or connection age.
It is designed particularly to resist the effects of variable latency (jitter). The Network Time Protocol (NTP) is a protocol for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. NTP uses UDP port 123 as its transport layer.
I’ve done this to run versions of Java. I use it for all my packet queuing, firewalls, logging and any other network gateway-. Linux Compatibility: Yes, FreeBSD offers Linux Compatibility. Binaries with the support installed and enabled. You can natively run linux. For you, FreeBSD works better.
If a SET_NUMBER is not specified, the rule will be added to set 0. Sets can be individually disabled or enabled, making it possible to quickly add or delete a set of rules. Each rule is associated with a set number from 0 to 31.