Essential System Administration Pocket Reference

Networking

ifconfig	ifconfig lo0 localhost up
ifconfig interface ip-address netmask mask
The first form configures the loopback interface. The second form assigns the specified IPv4 address and subnet mask to interface. FreeBSD and Solaris allow you to replace the address and netmask parameters (including the keywords) with a CIDR address.

Displaying information about network interfaces

ifconfig [options] [interface]

Display the configuration of the specified interface(s).

-a	Display data for all interfaces (not supported by HP-UX).
-l	(FreeBSD and AIX)
List all network interfaces.

Network interface configuration files

AIX:	Stored in the ODM; modify with mktcpip or SMIT.
FreeBSD:	/etc/rc.conf: hostname=″name″ifconfig_iface=″ip-addr netmask mask″
HP-UX:	/etc/rc.config.d/netconf: HOSTNAME=″name″INTERFACE_NAME[n]=nameIP_ADDRESS[n]=addrSUBNET_MASK[n]=maskINTERFACE_STATE[n]=up|down
n is the interface number (starting at 0).
Linux:	/etc/sysconfig/networking/devices/ifcfg-ethnRed Hat
/etc/sysconfig/network/ifcfg-ethn DEVICE=name                 Red HatBOOTPROTO=static|dhcpIPADDR=addrNETMASK=maskONBOOT=yes|no               Red Hat onlySTARTMODE=yes|no            SuSE only	SuSE
/etc/sysconfig/network: HOSTNAME=″name″	Red Hat
/etc/HOSTNAME:
Holds the hostname (SuSE).
Solaris:	/etc/hostname.iface:
The first line holds the hostname. Any additional line(s) hold ifconfig command arguments (optional).

Displaying the system’s MAC address