10.2.2 Restarting TCP/IP
TCP/IP is a peer-to-peer, connection-oriented protocol. There are no master/slave relations. The applications, however, use a client/server model for communications.
Removing the rc.tcpip entry in /etc/inittab means that you are not starting any server applications during IPL.
If you have a graphic console, make sure you also remove the rc.dt and rc.tcpip entries in the /etc/inittab file. Otherwise, your console will hang when you login. Unless you have an ASCII terminal connected to the serial port, there is no way you can recover since you will not be able to communicate with the machine through the telnet or rlogin commands with no TCP/IP server application started.
Without the server applications started, you will not be able to telnet or ftp to this machine from another host.
However, as long as you have not brought down the network interface, you can still utilize the client network services. You can still ping other hosts, you can still telnet to other hosts, and you can still ftp to other hosts.
The ping command sends an Internet Control Message Protocol (ICMP) ECHO_REQUEST to obtain an ICMP ECHO_RESPONSE from a host and does not need any server application. Therefore, even without starting any server application, the machine will still respond to a ping request from other hosts.
10.4 The inetd