FreeBSD Network Configuration

Interface Configuration

View Interfaces

# List all interfaces
ifconfig

# Specific interface
ifconfig em0

# Just interface names
ifconfig -l

Static IP Configuration

# /etc/rc.conf
ifconfig_em0="inet 192.168.1.100 netmask 255.255.255.0"
defaultrouter="192.168.1.1"

# Apply changes
service netif restart
service routing restart

DHCP Configuration

# /etc/rc.conf
ifconfig_em0="DHCP"

# Apply
service netif restart

Multiple IP Addresses

# /etc/rc.conf
ifconfig_em0="inet 192.168.1.100 netmask 255.255.255.0"
ifconfig_em0_alias0="inet 192.168.1.101 netmask 255.255.255.255"
ifconfig_em0_alias1="inet 192.168.1.102 netmask 255.255.255.255"

DNS Configuration

# /etc/resolv.conf
nameserver 8.8.8.8
nameserver 8.8.4.4
search example.com

# Prevent DHCP from overwriting
chflags schg /etc/resolv.conf

Routing

# View routing table
netstat -rn

# Add static route
route add -net 10.0.0.0/8 192.168.1.254

# Persistent routes in /etc/rc.conf
static_routes="internal"
route_internal="-net 10.0.0.0/8 192.168.1.254"

# Delete route
route delete -net 10.0.0.0/8

VLANs

# /etc/rc.conf
vlans_em0="100 200"
ifconfig_em0_100="inet 192.168.100.1 netmask 255.255.255.0"
ifconfig_em0_200="inet 192.168.200.1 netmask 255.255.255.0"

Bridging

# /etc/rc.conf
cloned_interfaces="bridge0"
ifconfig_bridge0="addm em0 addm em1 up"
ifconfig_em0="up"
ifconfig_em1="up"

Wireless Configuration

# /etc/rc.conf
wlans_ath0="wlan0"
ifconfig_wlan0="WPA DHCP"

# /etc/wpa_supplicant.conf
network={
    ssid="MyNetwork"
    psk="password"
}

Useful Commands

# Show active connections
sockstat -4

# Network statistics
netstat -s

# Check connectivity
ping -c 3 google.com

# DNS lookup
host google.com
drill google.com

# Trace route
traceroute google.com