Title: ifconfig
Before using an IP interface, the ifconfig utility should be used.
From ifconfig(8):
"The ifconfig utility initializes a TCP/IP device setting the IP address and/or netmask."
ifconfig makes the ioctl() system call:
result= ioctl(ip_fd, NWIOSIPCONF, &ipconf)
ifconfig has the following syntax:
ifconfig [-I ip-device] [-h ipaddr] [-n netmask] [-iv]
This command:
ifconfig -I /dev/ip1 -h 20.1.1.1 -n 255.255.255.0
assigns an IP address and a netmask to the "/dev/ip1" device file.
This command:
ifconfig -h 10.1.1.1 -n 255.255.255.0
assigns an IP address and a netmask to the default IP device (/dev/ip).