| Certification Summary The TCP/IP protocol suite makes the Internet appear to be a big single
network to millions of users, even though underneath it is a collection of
heterogeneous networks. TCP/IP protocols are organized into five layers that
closely correspond to the seven layers of the OSI reference model. Each machine
has hardware (MAC) address (defined in the data link layer), which is its
identity on a LAN, and an IP address (defined in the network layer) which is its
identity on the Internet. Furthermore, a frame (data packet defined in the data
link layer) can only be delivered locally, and an IP datagram (a data packet
defined in the network layer) can be sent across multiple networks—that is, over
the Internet. Each router on the way reframes the datagram as it hops from
network to network on its route from source to destination.
You can view the packet traffic on the inbound/outbound connections of your
machine by using the netstat command, and if you suspect a problem you can use
the ping command to test the reachability of another host. You can also use the
snoop command to look into the header of a packet. The packets that you can
monitor by using these commands enter or exit through an interface that you can
configure by using the ifconfig command.
Once your system is connected to the network through interfaces that you have
configured, you need to manage the services running on your system. Standard
Internet services are started by inetd at boot time. Solaris 10 offers Services
Management Facility (SMF), which augments the traditional UNIX startup scripts
and configuration files. The inetadm command is used to manage the inetd
controlled services, and svcadm is the SMF utility used to manage the network
services.
It's easier to remember a machine on the network by a name rather than by IP
address. An entry in the /etc/inet/hosts file on your system contains the
following information about a host name associated with your machine: the host
name, the corresponding IP address, and an alias for the host name, if any. This
file needs entries about other machines on the network only if the network is
using the local files for the name service. Usually the network uses the NIS and
DNS name services, which maintain host names and addresses on one or more
servers. We explore the name services in the next chapter. | 
