12.8. Setting Up Network Interface Cards

Contributed by Marc Fonvieille.

Adding and configuring a network interface card (NIC) is a common task for any FreeBSD administrator.

12.8.1. Locating the Correct Driver

First, determine the model of the NIC and the chip it uses. FreeBSD supports a wide variety of NICs. Check the Hardware Compatibility List for the FreeBSD release to see if the NIC is supported.

If the NIC is supported, determine the name of the FreeBSD driver for the NIC. Refer to /usr/src/sys/conf/NOTES and /usr/src/sys/arch/conf/NOTES for the list of NIC drivers with some information about the supported chipsets. When in doubt, read the manual page of the driver as it will provide more information about the supported hardware and any known limitations of the driver.

The drivers for common NICs are already present in the GENERIC kernel, meaning the NIC should show up during boot. In this example, two NICs using the dc(4) driver are present on the system:

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]

If the driver for the NIC is not present in GENERIC, but a driver is available, the driver will need to be loaded before the NIC can be configured and used. This may be accomplished in one of two ways:

  • The easiest way is to load a kernel module for the NIC using kldload(8). To also automatically load the driver at boot time, add the appropriate line to /boot/loader.conf. Not all NIC drivers are available as modules.

  • Alternatively, statically compile support for the NIC into a custom kernel. Refer to /usr/src/sys/conf/NOTES, /usr/src/sys/arch/conf/NOTES and the manual page of the driver to determine which line to add to the custom kernel configuration file. For more information about recompiling the kernel, refer to Chapter 9, Configuring the FreeBSD Kernel. If the NIC was detected at boot, the kernel does not need to be recompiled. 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 with two choices: develop the drivers by a long and pain-staking process of reverse engineering or using the existing driver binaries available for Microsoft® Windows® platforms.

FreeBSD provides native support for the Network Driver Interface Specification (NDIS). It includes ndisgen(8) which can be used to convert a Windows® XP driver into a format that can be used on FreeBSD. Because the ndis(4) driver uses a Windows® XP binary, it only runs on i386™ and amd64 systems. PCI, CardBus, PCMCIA, and USB devices are supported.

To use ndisgen(8), three things are needed:

  1. FreeBSD kernel sources.

  2. A Windows® XP driver binary with a .SYS extension.

  3. A Windows® XP driver configuration file with a .INF extension.

Download the .SYS and .INF files for the specific NIC. Generally, these can be found on the driver CD or at the vendor's website. The following examples 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

This command is interactive and prompts for any extra information it requires. A new kernel module will be generated in the current directory. Use kldload(8) to load the new module:

# kldload ./W32DRIVER_SYS.ko

In addition to the generated kernel module, the ndis.ko and if_ndis.ko modules must be loaded. This should happen automatically when any module that depends on ndis(4) is loaded. If not, load them manually, using the following commands:

# kldload ndis # kldload if_ndis

The first command loads the ndis(4) miniport driver wrapper and the second loads the generated NIC driver.

Check dmesg(8) to see if there were any load errors. If all went well, the output should be similar to 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, ndis0 can be configured like any other NIC.

To configure the system to load the ndis(4) modules at boot time, copy the generated module, W32DRIVER_SYS.ko, to /boot/modules. Then, add the following line to /boot/loader.conf:


12.8.2. Configuring the Network Card

Once the right driver is loaded for the NIC, the card needs to be configured. It may have been configured at installation time by sysinstall(8).

To display the NIC configuration, enter the following command:

% ifconfig dc0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=80008<VLAN_MTU,LINKSTATE> 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 options=80008<VLAN_MTU,LINKSTATE> ether 00:a0:cc:da:da:db inet netmask 0xffffff00 broadcast media: Ethernet 10baseT/UTP status: no carrier lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 options=3<RXCSUM,TXCSUM> 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:

  • dc0: The first Ethernet interface.

  • dc1: The second Ethernet interface.

  • lo0: The loopback device.

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

In this example, dc0 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,

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

  4. It has a valid broadcast address,

  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>)). In this example, dc1 is configured to run with 10baseT/UTP media. For more information on available media types for a driver, refer to its manual page.

  7. The status of the link (status) is active, indicating that the carrier signal is detected. For dc1, the status: no carrier status 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 options=80008<VLAN_MTU,LINKSTATE> ether 00:a0:cc:da:da:da media: Ethernet autoselect (100baseTX <full-duplex>) status: active

it would indicate the card has not been configured.

The card must be configured as root. The NIC configuration can be performed from the command line with ifconfig(8) but will not persist after a reboot unless the configuration is also added to /etc/rc.conf. Add a line for each NIC present on the system, as seen in this example:

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

Replace dc0 and dc1 and the IP address information with the correct values for the system. Refer to the man page for the driver, ifconfig(8), and rc.conf(5) for more details about the allowed options and the syntax of /etc/rc.conf.

If the network was configured during installation, some entries for the NIC(s) may be already present. Double check /etc/rc.conf before adding any lines.

If the network is not using DNS, edit /etc/hosts to add the names and IP addresses of of the hosts on the LAN, if they are not already there. For more information, refer to hosts(5) and to /usr/share/examples/etc/hosts.


If there is no DHCP server and access to the Internet is needed, manually configure 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 the necessary changes to /etc/rc.conf are saved, a reboot can be used to test the network configuration and to verify that the system restarts without any configuration errors. Alternatively, apply the settings to the networking system with this command:

# service netif restart


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

# service routing restart

Once the networking system has been relaunched, test the NICs. Testing the Ethernet Card

To verify that an Ethernet card is configured correctly, ping(8) the interface itself, and then ping(8) another machine on the LAN:

% 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
% 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

To test network resolution, use the host name instead of the IP address. If there is no DNS server on the network, /etc/hosts must first be configured. Troubleshooting

When troubleshooting hardware and software configurations, check the simple things first. Is the network cable plugged in? Are the network services properly configured? Is the firewall configured correctly? Is the NIC supported by FreeBSD? Before sending a bug report, always check the Hardware Notes, update the version of FreeBSD to the latest STABLE version, check the mailing list archives, and search the Internet.

If the card works, yet performance is poor, read through tuning(7). 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, determine if the device is conflicting with another device. Double check the cable connections. Consider trying another card.

To resolve watchdog timeout errors, first check the 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 NIC 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. If there is not, read Chapter 31, Advanced Networking.

ping: sendto: Permission denied error messages are often caused by a misconfigured firewall. If a firewall is enabled on FreeBSD but no rules have been defined, the default policy is to deny all traffic, even ping(8). Refer to Chapter 30, Firewalls for more information.

Sometimes performance of the card is poor or below average. In these cases, try setting the media selection mode from autoselect to the correct media selection. While this works for most hardware, it may or may not resolve the issue. Again, check all the network settings, and refer to tuning(7).

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