ifconfig is used to make an interface accessible to the kernel networking layer. This involves the assignment of an IP-address and other parameters, and activating the interface, also known as ``taking up.'' Being active here means that the kernel will send and receive IP-datagrams through the interface. The simplest way to invoking it is
ifconfig interface ip-address
which assigns ip-address to interface and activates it.
All other parameters are set to default values. For instance, the
default subnet mask is derived from the network class of the IP-address,
such as 255.255.0.0 for a class-B address. ifconfig is
described in detail at the end of this chapter.
route allows you to add or remove routes from the kernel routing table. It can be invoked as
route [add|del] target
where the add and del arguments determine whether
to add or delete the route to target.