Name Resolution

RPC Manager uses name resolution to discover the IP for a particular machine name. The correct configuration of name resolution services is outside the scope of this document. Reference should be made to the operating system documentation.

Caution: A correctly configured name resolution system is essential for correct operation of the distributed system.

The default name resolution setup for Windows TCP/IP networks looks in the following places, in the following order, to derive an IP address:

1. The operating system HOSTS file is searched.
2. If not found, any configured domain name servers (DNS) are checked (including WINS servers).
3. If still not found, NetBIOS broadcasting is used.

If you do not configure any name resolution system, the default behavior of Windows will cause NetBIOS broadcasts to be used. While this will work fine on most network configurations, it may not work properly on large, segmented networks.

The basic rule is that if you can reliable ping a machine by name and have the correct IP addressed by the ping packets, then VTScada will work correctly.

Most SCADA systems will function well with static IP to name mapping. This can be achieved through HOSTS files on individual machines, or by a centralized name resolution service, such as WINS.

VTScada will, however, also function correctly with dynamic IP address assignment, typically provided by DHCP. RAS clients also often use dynamic IP assignment when connected into a RAS server.

If NetBIOS broadcasting is insufficient to meet your name resolution needs, then you will need to consider one of the alternatives in the following topics: