Determining whether your system has access

Edit online

Use the host to determine whether your system has access to information that defines the other system.

To access another system on the network, your local system must have access to information that defines the other system. To determine if your local system has this information, enter the host command with the name of the other system.

To determine if your local system has routing information for system zeus, enter: 
host zeus
If your system has the proper information, a display similar to the following is returned:
zeus is 192.9.200.4 (300,11,310,4)
You can then send a message to system zeus. The address 192.9.200.4 is used by the system to route the mail. If your system does not have the information, a display similar to the following is returned:
zeus: unknown host
If you receive an unknown host message, then the requested system name:
  • Is not correct (check the spelling in the address)
  • Is on your network but not defined to your system (contact the person responsible for setting up your network)
  • Is on another network (see Addressing mail to users on a different network) and requires more detailed addressing
  • Is not connected to your network

You can also receive the unknown host message if your network is not operating and your local system depends on a remote system to supply network addresses.