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Network Configuration—BasicsLogical network interfaces include the following:• Loopback interface• Tunnel interfaces (for example GRE, PPP, GIF, and FAITH,)• VLAN interfaces• Bridge interfaces.The Ifconfig utility is used to display the current status of any interface that isinstalled on the system. For example, to figure out what interfaces are available onyour system, you may use the following command:# ifconfig -lfxp0 xl0 plip0 lo0The system in the above example has four network interfaces, out of which two(fxp0 and xl0) are physical while the other two (plip0 and lo0) arelogical interfaces.In FreeBSD, network interfaces are named after their driver. For example,Intel NICs are identified as fxp, Broadcom Gigabit NICs as bge, andso on.The Ifconfig utility can also be used to display the detailed status of an interface asshown here:# ifconfig fxp0fxp0: flags=8843 mtu 1500options=binet6 fe80::20c:29ff:fefd:f61d%em0 prefixlen 64 scopeid 0x1inet 198.168.0.5 netmask 0xffffff00 broadcast 198.18.0.255ether 00:0c:29:fd:f6:1dmedia: Ethernet autoselect (100baseTX )status: activeThe above interface summary displays an fxp (Intel family) network interfacethat has both IPv4 (inet) and IPv6 (inet6) addresses configured. Other informationincluding MAC address (ether) and media specific options are also displayed.A list of important interface flags is listed in the following table:Flag nameUPBROADCASTDescriptionIndicates that the interface's Layer3 protocol is up.Indicates that the broadcast address is valid. Not used forpoint-to-point interfaces.[ 102 ]