The first command to enter on both the server and the client is
ping 127.0.0.1. This is the
loopback
address and testing it will indicate whether any networking support is functioning at all. On Unix, you can use
ping
127.0.0.1 with the statistics option and interrupt it after a few lines. On Sun workstations, the command is typically
/usr/etc/ping
-s
127.0.0.1; on Linux, just
ping
127.0.0.1. On Windows clients, run
ping
127.0.0.1 in an MS-DOS window and it will stop by itself after four lines.
Here is an example on a Linux server:
server% ping 127.0.0.1
PING localhost: 56 data bytes 64 bytes from localhost (127.0.0.1):
icmp-seq=0. time=1. ms 64 bytes from localhost (127.0.0.1):
icmp-seq=1. time=0. ms 64 bytes from localhost (127.0.0.1):
icmp-seq=2. time=1. ms ^C
----127.0.0.1 PING Statistics----
3 packets transmitted, 3 packets received, 0% packet loss round-trip (ms)
min/avg/max = 0/0/1
If you get "ping: no answer from..." or "100% packet loss," you have no IP networking at all installed on the machine. The address
127.0.0.1 is the internal loopback address and doesn't depend on the computer being physically connected to a network. If this test fails, you have a serious local problem. TCP/IP either isn't installed or is seriously misconfigured. See your operating system documentation if it is a Unix server. If it is a Windows client, follow the instructions in Chapter 3,
Configuring Windows Clients, to install networking support.
If
you're the network manager, some good references are Craig Hunt's
TCP/IP Network Administration, Chapter 11, and Craig Hunt & Robert Bruce Thompson's new book,
Windows NT TCP/IP Network Administration, both published by O'Reilly.
