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## Determining the host name

There are many different network naming schemes and each major operating system type seems to have its own variant. While being largely compatible, the network naming schemes sometimes present problems when you attempt to use a computer that has one idea of what its name is with another computer that may use a somewhat different network naming scheme. Since VisIt users are encouraged to use distributed mode because it provides fast local graphics hardware without sacrificing computing power, VisIt must provide a way to reconcile the network naming schemes when 2 different computer types are used.

Workstations often have a host name that was arbitrarily set when the computer was installed and that host name has nothing to do with the computer's network name, which ultimately resolves to an IP address. This condition is common on computers running MS Windows though other operating systems can also exhibit this behavior. When VisIt launches a component on a remote computer, it passes information that includes the host name of the local computer so the remote component will know how to connect back to the local computer. If the local computer did not supply a valid network name then the remote component will not be able to connect back to the local computer and VisIt will wait for the connection until you click the Cancel button in the Launch progress window.

By default, VisIt relies on the name obtained from the local computer but if you want to specify a name instead of using the name reported by the local computer then you can use the controls on the Advanced options tab. To use a host name other than what the local computer returns, you can click the Parse from SSH_CLIENT environment variable or Specify manually radio buttons. If you choose the Parse from SSH_CLIENT environment variable option then VisIt will not pass a host name for the local computer but will instead tell the remote computer to inspect the SSH_CLIENT environment variable to determine the IP address of the local computer that initiated the connection. This option usually works if you have a local computer that does not accurately report its host name. If you don't trust the output of any implicit scheme for getting the local computer's name, you can provide the name of the local computer by typing its name or IP address into the text field next to the Specify manually radio button.