.. include:: ../../vars.rst
.. _section-administration-ref-host-name-process-id:

Host Names and Process IDs
==========================

|AC| uses the familiar concepts of *hosts* and *processes* to organize
information displayed in the user interface. Processes determined to be running
on the same host are grouped together to make it easier to find information.
The host name and the process ID are derived from information available to
|AC| at runtime.

**Determining Host Name and Process ID:**

Internally, |AC| receives Discovery information, primarily composed of data
regarding *DomainParticipants*, *DataReaders*, and *DataWriters*.

As part of the *DomainParticipant* information, there are system
properties that provide |AC| with the host name and process
ID; however, these properties can be disabled through QoS
configuration. If that is the case, |AC| tries to fill in the
missing information in a couple of different ways. 

In versions before 6.0.0, |AC| uses the *DomainParticipant*'s
identity (GUID) to determine the host IP address and process ID. The
host IP address is then used to try to determine a host name (in a
process similar to an *nslookup*).

This method is not always accurate and may result in an unexpected
host name shown in the user interface.

From version 6.0.0 forward, if the necessary information isn't provided in
the system properties, |AC| uses "unknown-host" for the host name
and zero for the process ID. This is an attempt to more accurately reflect
what information is known. If you see either of these values in the user
interface, please reconfigure your QoS settings to allow the system
properties to reach |AC|.