11.8 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.

11.8.1 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.

Note: NOTES does not exist on FreeBSD 4.X. Instead, check the LINT file for information about various network interfaces. See Section 8.4 for a more detailed summary of NOTES versus LINT.

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
dc0: Ethernet address: 00:a0:cc:da:da:da
miibus0: <MII bus> on dc0
ukphy0: <Generic IEEE 802.3u media interface> on miibus0
ukphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
dc1: <82c169 PNIC 10/100BaseTX> port 0x9800-0x98ff mem 0xd3000000-0xd30
000ff irq 11 at device 12.0 on pci0
dc1: Ethernet address: 00:a0:cc:da:da:db
miibus1: <MII bus> on dc1
ukphy1: <Generic IEEE 802.3u media interface> on miibus1
ukphy1:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto

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:

11.8.2 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
        inet netmask 0xffffff00 broadcast
        ether 00:a0:cc:da:da:da
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
        inet netmask 0xffffff00 broadcast
        ether 00:a0:cc:da:da:db
        media: Ethernet 10baseT/UTP
        status: no carrier
lp0: flags=8810<POINTOPOINT,SIMPLEX,MULTICAST> mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet netmask 0xff000000
tun0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500

Note: Old versions of FreeBSD may require the -a option following ifconfig(8), for more details about the correct syntax of ifconfig(8), please refer to the manual page. Note also that entries concerning IPv6 (inet6 etc.) were omitted in this example.

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> mtu 1500
            ether 00:a0:cc:da:da:da

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.

11.8.3 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.

Once the system has been rebooted, 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 25.

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 24 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.

This, and other documents, can be downloaded from ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/.

For questions about FreeBSD, read the documentation before contacting <questions@FreeBSD.org>.
For questions about this documentation, e-mail <doc@FreeBSD.org>.

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Generated: 2007-01-26 17:58:42