What is DCOM in VB?

Distributed Component Object Model (DCOM) is an extension to Component Object Model (COM) that enables software components to communicate with each other across different computers on a local area network (LAN), on a wide area network (WAN) or across the internet.

What is COM DCOM tutorial?

What is DCOM?

COM is a set of components tools which are executed on client-side environment. DCOM runs on the given server.
COM objects require installation on machine where it is to be used. It requires installation somewhere on the same network.

Is DCOM still supported?

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Why is DCOM necessary?

Why DCOM? Because the vast majority of personal computers are PCs running Windows – the primary target of DCOM. DCOM provides the ability to use and reuse components dynamically, without recompiling, on any platform, from any language, at any time. This is perhaps the single most important aspect of DCOM.

What is difference between COM and DCOM?

The distributed component object model is specifically designed for distributed applications. Before DCOM was known as “Network OLE”.

Difference between COM and DCOM :

Basis of COM DCOM
Model type COM is an interface standard. DCOM a model designed for distributed applications.
Object reusability It allows. It does not allows.

Which applications use DCOM?

DCOM is supported natively in Windows NT 4.0, Windows 2000, Windows XP, and Windows Server 2003. Warning If you disable DCOM, may you may lose operating system functionality. After you disable support for DCOM, the following may result: Any COM objects that can be started remotely may not function correctly.

Is DCOM a protocol?

The Distributed Component Object Model (DCOM) is a protocol that enables software components to communicate directly over a network in a reliable, secure, and efficient manner. Previously called “Network OLE,” DCOM is designed for use across multiple network transports, including Internet protocols such as HTTP.

What port is DCOM?

Port 135

DCOM uses Port 135 to establish communication. Once the OPC Client and Server are able to communicate, they will negotiate new port numbers for communication dynamically.


DCOM relies on dynamically-assigned TCP ports. When an OPC client connects to an OPC server, it connects to port 135 (the RPC port mapper), which assigns one TCP port and one UDP port to the component.

Does DCOM use TCP?

TCP port 135 is the DCE endpoint resolution point that is used by DCOM. By default, DCOM assigns ports dynamically from the TCP port range of 1024 through 65535. However, you can use Component Services to adjust the TCP port range.