12.8 Setting Up Network Interface Cards

Contributed by Marc Fonvieille.

Nowadays we can not think about a computer without thinking about a network connection. Adding and configuring a network card is a common task for any FreeBSD administrator.

12.8.1 Locating the Correct Driver

Before you begin, you should know the model of the card you have, the chip it uses, and whether it is a PCI or ISA card. FreeBSD supports a wide variety of both PCI and ISA cards. Check the Hardware Compatibility List for your release to see if your card is supported.

Once you are sure your card is supported, you need to determine the proper driver for the card. /usr/src/sys/conf/NOTES and /usr/src/sys/arch/conf/NOTES will give you the list of network interface drivers with some information about the supported chipsets/cards. If you have doubts about which driver is the correct one, read the manual page of the driver. The manual page will give you more information about the supported hardware and even the possible problems that could occur.

If you own a common card, most of the time you will not have to look very hard for a driver. Drivers for common network cards are present in the GENERIC kernel, so your card should show up during boot, like so:

dc0: <82c169 PNIC 10/100BaseTX> port 0xa000-0xa0ff mem 0xd3800000-0xd38
000ff irq 15 at device 11.0 on pci0
miibus0: <MII bus> on dc0
bmtphy0: <BCM5201 10/100baseTX PHY> PHY 1 on miibus0
bmtphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
dc0: Ethernet address: 00:a0:cc:da:da:da
dc0: [ITHREAD]
dc1: <82c169 PNIC 10/100BaseTX> port 0x9800-0x98ff mem 0xd3000000-0xd30
000ff irq 11 at device 12.0 on pci0
miibus1: <MII bus> on dc1
bmtphy1: <BCM5201 10/100baseTX PHY> PHY 1 on miibus1
bmtphy1:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
dc1: Ethernet address: 00:a0:cc:da:da:db
dc1: [ITHREAD]

In this example, we see that two cards using the dc(4) driver are present on the system.

If the driver for your NIC is not present in GENERIC, you will need to load the proper driver to use your NIC. This may be accomplished in one of two ways: Using Windows® NDIS Drivers

Unfortunately, there are still many vendors that do not provide schematics for their drivers to the open source community because they regard such information as trade secrets. Consequently, the developers of FreeBSD and other operating systems are left two choices: develop the drivers by a long and pain-staking process of reverse engineering or using the existing driver binaries available for the Microsoft® Windows platforms. Most developers, including those involved with FreeBSD, have taken the latter approach.

Thanks to the contributions of Bill Paul (wpaul) there is “native” support for the Network Driver Interface Specification (NDIS). The FreeBSD NDISulator (otherwise known as Project Evil) takes a Windows driver binary and basically tricks it into thinking it is running on Windows. Because the ndis(4) driver is using a Windows binary, it only runs on i386™ and amd64 systems. PCI, CardBus, PCMCIA (PC-Card), and USB devices are supported.

To use the NDISulator, three things are needed:

  1. Kernel sources

  2. Windows XP driver binary (.SYS extension)

  3. Windows XP driver configuration file (.INF extension)

Locate the files for your specific card. Generally, they can be found on the included CDs or at the vendor's website. In the following examples, we will use W32DRIVER.SYS and W32DRIVER.INF.

The driver bit width must match the version of FreeBSD. For FreeBSD/i386, use a Windows 32-bit driver. For FreeBSD/amd64, a Windows 64-bit driver is needed.

The next step is to compile the driver binary into a loadable kernel module. As root, use ndisgen(8):

# ndisgen /path/to/W32DRIVER.INF /path/to/W32DRIVER.SYS

ndisgen(8) is interactive and prompts for any extra information it requires. A new kernel module is written in the current directory. Use kldload(8) to load the new module:

# kldload ./W32DRIVER_SYS.ko

In addition to the generated kernel module, you must load the ndis.ko and if_ndis.ko modules. This should be automatically done when you load any module that depends on ndis(4). If you want to load them manually, use the following commands:

# kldload ndis
# kldload if_ndis

The first command loads the NDIS miniport driver wrapper, the second loads the actual network interface.

Now, check dmesg(8) to see if there were any errors loading. If all went well, you should get output resembling the following:

ndis0: <Wireless-G PCI Adapter> mem 0xf4100000-0xf4101fff irq 3 at device 8.0 on pci1
ndis0: NDIS API version: 5.0
ndis0: Ethernet address: 0a:b1:2c:d3:4e:f5
ndis0: 11b rates: 1Mbps 2Mbps 5.5Mbps 11Mbps
ndis0: 11g rates: 6Mbps 9Mbps 12Mbps 18Mbps 36Mbps 48Mbps 54Mbps

From here you can treat the ndis0 device like any other network interface (e.g., dc0).

You can configure the system to load the NDIS modules at boot time in the same way as with any other module. First, copy the generated module, W32DRIVER_SYS.ko, to the /boot/modules directory. Then, add the following line to /boot/loader.conf:


12.8.2 Configuring the Network Card

Once the right driver is loaded for the network card, the card needs to be configured. As with many other things, the network card may have been configured at installation time by sysinstall.

To display the configuration for the network interfaces on your system, enter the following command:

% ifconfig
dc0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 00:a0:cc:da:da:da
        inet netmask 0xffffff00 broadcast
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
dc1: flags=8802<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 00:a0:cc:da:da:db
        inet netmask 0xffffff00 broadcast
        media: Ethernet 10baseT/UTP
        status: no carrier
plip0: flags=8810<POINTOPOINT,SIMPLEX,MULTICAST> metric 0 mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x4
        inet6 ::1 prefixlen 128
        inet netmask 0xff000000
        nd6 options=3<PERFORMNUD,ACCEPT_RTADV>

In this example, the following devices were displayed:

FreeBSD uses the driver name followed by the order in which one the card is detected at the kernel boot to name the network card. For example sis2 would be the third network card on the system using the sis(4) driver.

In this example, the dc0 device is up and running. The key indicators are:

  1. UP means that the card is configured and ready.

  2. The card has an Internet (inet) address (in this case

  3. It has a valid subnet mask (netmask; 0xffffff00 is the same as

  4. It has a valid broadcast address (in this case,

  5. The MAC address of the card (ether) is 00:a0:cc:da:da:da

  6. The physical media selection is on autoselection mode (media: Ethernet autoselect (100baseTX <full-duplex>)). We see that dc1 was configured to run with 10baseT/UTP media. For more information on available media types for a driver, please refer to its manual page.

  7. The status of the link (status) is active, i.e., the carrier is detected. For dc1, we see status: no carrier. This is normal when an Ethernet cable is not plugged into the card.

If the ifconfig(8) output had shown something similar to:

dc0: flags=8843<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 00:a0:cc:da:da:da
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

it would indicate the card has not been configured.

To configure your card, you need root privileges. The network card configuration can be done from the command line with ifconfig(8) but you would have to do it after each reboot of the system. The file /etc/rc.conf is where to add the network card's configuration.

Open /etc/rc.conf in your favorite editor. You need to add a line for each network card present on the system, for example in our case, we added these lines:

ifconfig_dc0="inet netmask"
ifconfig_dc1="inet netmask media 10baseT/UTP"

You have to replace dc0, dc1, and so on, with the correct device for your cards, and the addresses with the proper ones. You should read the card driver and ifconfig(8) manual pages for more details about the allowed options and also rc.conf(5) manual page for more information on the syntax of /etc/rc.conf.

If you configured the network during installation, some lines about the network card(s) may be already present. Double check /etc/rc.conf before adding any lines.

You will also have to edit the file /etc/hosts to add the names and the IP addresses of various machines of the LAN, if they are not already there. For more information please refer to hosts(5) and to /usr/share/examples/etc/hosts.

Note: If access to the Internet is planned with the machine, you also have to manually set up the default gateway and the nameserver:

# echo 'defaultrouter="your_default_router"' >> /etc/rc.conf
# echo 'nameserver your_DNS_server' >> /etc/resolv.conf

12.8.3 Testing and Troubleshooting

Once you have made the necessary changes in /etc/rc.conf, you should reboot your system. This will allow the change(s) to the interface(s) to be applied, and verify that the system restarts without any configuration errors. Alternatively you can just relaunch the networking system:

# /etc/rc.d/netif restart

Note: If a default gateway has been set in /etc/rc.conf, use also this command:

# /etc/rc.d/routing restart

Once the networking system has been relaunched, you should test the network interfaces. Testing the Ethernet Card

To verify that an Ethernet card is configured correctly, you have to try two things. First, ping the interface itself, and then ping another machine on the LAN.

First test the local interface:

% ping -c5
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=0.082 ms
64 bytes from icmp_seq=1 ttl=64 time=0.074 ms
64 bytes from icmp_seq=2 ttl=64 time=0.076 ms
64 bytes from icmp_seq=3 ttl=64 time=0.108 ms
64 bytes from icmp_seq=4 ttl=64 time=0.076 ms

--- ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.074/0.083/0.108/0.013 ms

Now we have to ping another machine on the LAN:

% ping -c5
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=0.726 ms
64 bytes from icmp_seq=1 ttl=64 time=0.766 ms
64 bytes from icmp_seq=2 ttl=64 time=0.700 ms
64 bytes from icmp_seq=3 ttl=64 time=0.747 ms
64 bytes from icmp_seq=4 ttl=64 time=0.704 ms

--- ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.700/0.729/0.766/0.025 ms

You could also use the machine name instead of if you have set up the /etc/hosts file. Troubleshooting

Troubleshooting hardware and software configurations is always a pain, and a pain which can be alleviated by checking the simple things first. Is your network cable plugged in? Have you properly configured the network services? Did you configure the firewall correctly? Is the card you are using supported by FreeBSD? Always check the hardware notes before sending off a bug report. Update your version of FreeBSD to the latest STABLE version. Check the mailing list archives, or perhaps search the Internet.

If the card works, yet performance is poor, it would be worthwhile to read over the tuning(7) manual page. You can also check the network configuration as incorrect network settings can cause slow connections.

Some users experience one or two “device timeout” messages, which is normal for some cards. If they continue, or are bothersome, you may wish to be sure the device is not conflicting with another device. Double check the cable connections. Perhaps you may just need to get another card.

At times, users see a few “watchdog timeout” errors. The first thing to do here is to check your network cable. Many cards require a PCI slot which supports Bus Mastering. On some old motherboards, only one PCI slot allows it (usually slot 0). Check the network card and the motherboard documentation to determine if that may be the problem.

No route to host” messages occur if the system is unable to route a packet to the destination host. This can happen if no default route is specified, or if a cable is unplugged. Check the output of netstat -rn and make sure there is a valid route to the host you are trying to reach. If there is not, read on to Chapter 32.

ping: sendto: Permission denied” error messages are often caused by a misconfigured firewall. If ipfw is enabled in the kernel but no rules have been defined, then the default policy is to deny all traffic, even ping requests! Read on to Chapter 31 for more information.

Sometimes performance of the card is poor, or below average. In these cases it is best to set the media selection mode from autoselect to the correct media selection. While this usually works for most hardware, it may not resolve this issue for everyone. Again, check all the network settings, and read over the tuning(7) manual page.