20.1 What is DHost?

NetIQ eDirectory software for Windows and Linux is all built upon the same core code. In order for eDirectory for Windows and Linux to properly interact with the other versions of eDirectory, they support a subset of NetWare Core Protocol (NCP) services. This is handled by a program called DHost. DHost sits beneath eDirectory and provides functionality that the NCP provides naturally.

DHost provides the following services:



NCP Engine

A packet-based protocol that enables a client to send requests to and receive replies from an eDirectory server.

For more information, see the NetWare Core Protocols NDK.


Packets used to make sure workstations are still connected to the eDirectory server.

For more information, see “Watchdog Packet Spoofing”.

Connection Table

A unique number assigned to any process, print server, application, workstation, or other entity that attaches to an eDirectory server. The number can be different each time an attachment is made. Connection numbers are used in implementing network security and for network accounting. They reflect the objects place in the file servers connection table. Additionally, they provide an easy way to identify and obtain information about the objects logged in on the network.

Event System

Provides a way for applications to monitor the activity of an individual server.

Thread Pool

A sequence of instructions executed as an independent entity and scheduled by system software.

NCP Extensions

Allows server application developers to write NLM™ software to be implemented as NCPs.

For more information, see “NCP Extension” in the NCP NDK.

Message Digest

A compressed or condensed form of a document, or an abstract from a document, that functions as a “digital fingerprint” of the larger document. A message digest is used to create a digital signature that is unique to a particular document.