3. If the PING operation is successful, you should see messages similar to those
in Figure 26.
If the PING operation is unsuccessful, you should see messages similar to
those in Figure 27.
If you receive an unsuccessful PING message, check your configuration steps.
Also check that the configuration at the remote system is correct and that the
remote system is not powered down. For additional information about identifying
the cause for an unsuccessful connection verification, see 437.
Note: A datagram sent by TCPor UDP to a system with the name LOOPBACK
does not actually leave the system. The IP layer,instead, returns the
datagram to the TCP or UDP layer from which it came. The other layers then
treat the datagram as a normal incoming datagram. The LOOPBACK host
name can be used with any TCP/IP command requiring a system name,
such as PING or FTP (or any TCP or UDP application including user-written
applications). Using the LOOPBACK default host name provides an ability to
test TCP/IP applications without actually connecting to a physical network.
The AS/400 system defines LOOPBACK as the default host name by automatically
creating an entry in the local host table.
Verifying Additional TCP/IP Connections
Once TCP/IP is configured on theAS/400 system, and the initial connection is
verified, you will probably want to add more systems to your network. When you
connect additional systems to your network, you also need to verify their TCP/IP
connection. The examples in the following paragraphs show you how to verify a
remote TCP/IP connection.
> ping '9.4.73.212'
Verifying connection to host system 9.4.73.212.
PING request 1 from 9.4.73.212 took 24 ms. 256 bytes. TTL 64.
PING request 2 from 9.4.73.212 took 11 ms. 256 bytes. TTL 64.
PING request 3 from 9.4.73.212 took 31 ms. 256 bytes. TTL 64.
PING request 4 from 9.4.73.212 took 11 ms. 256 bytes. TTL 64
PING request 5 from 9.4.73.212 took 12 ms. 256 bytes. TTL 64.
Round-trip (in milliseconds) min/avg/max = 11/17/31
Connection verification statistics: 5 of 5 successful (100 %).
Figure 26. Successful PING Messages
> ping '9.4.73.198'
Verifying connection to host system 9.4.73.198.
No response from host within 1 seconds for connection verification 1.
No response from host within 1 seconds for connection verification 2.
No response from host within 1 seconds for connection verification 3.
No response from host within 1 seconds for connection verification 4.
No response from host within 1 seconds for connection verification 5.
Connection verification statistics: 0 of 5 successful (0 %).
Bottom
Figure 27. Unsuccessful PING Messages
Chapter2. Configuring TCP/IP 47