DCOM and protocol specification
Huseyin Caglayan
Hi,
Does anyone know an easy way of instructing DCOM to use a specific protocol
when specifying a remote machine name?
I want to be able to specify the underlying protocol (TCP/IP or NetBEUI in
this case) when I call CoCreateInstanceEx.
Thanks.
--
The team that created 'Always Imagine'
Please reply by e-mail too.
Dr Richard Grimes
A DCOM NT machine will have several protocols installed, though maybe not
loaded. Any of these can be used and the preferred order is given in
HKLM\Software\Microsoft\Rpc. You can edit this to specify the preferred
protocal as the first one in the list. (Win95 only uses TCP/IP as the
protocol.)
There you will find a named value called "DCOM Protocols" you can edit this
to put the protocols in the order you need (use RegEdt32 rather than RegEdit
because it will allow you to edit a multistring as multiple strings rather
than as binary data).
However, this will affect *all* objects you are the client of or the server
of. DCOM is built over Microsoft RPC. If you write an RPC client to conncet
ot an RPC server you can supply RPC endpoint binding information, which
gives the protocol as well as the endpoint. This information is also used as
part of the MEOW packet sent between the the client and server machines.
Endpoints are defined by the Object Exporter. The interfaces are not
publicized (or at least the ones in the SDK have changed...) and I don't
know if anyone has actually managed to call the exporter directly. Its
something I hope to try soon...
Richard
--
Dr Richard Grimes
Co-author (with Alex Stockton) of "Beginners ATL COM Programming"
see http://www.wrox.com
Huseyin Caglayan wrote in message <01bd0ee5$7d202440$04010101@huseyin>...
Johannes Stratmann
Dr Richard Grimes schrieb in Nachricht
<883687473.1935.0...@news.demon.co.uk>...
>A DCOM NT machine will have several protocols installed, though maybe not
>loaded. Any of these can be used and the preferred order is given in
>HKLM\Software\Microsoft\Rpc. You can edit this to specify the preferred
>protocal as the first one in the list. (Win95 only uses TCP/IP as the
>protocol.)
It's a feature that the transport layer is transparent, but I think for a
lot of applications it would be great to have some more control over the
used protocoll, alive-pings, timeouts and error retries. Aren't there more
requests about that ?
Michael Nelson
Yes there are quite a few requests for those features, but there are only so
many days in the year and so many people to implement features :-). Some of
this stuff is being worked on in NT 5.0 -- support for Async DCOM will go a
long way toward ameliorating these problems.
-mike
Johannes Stratmann wrote in message
<#xNdhdiG...@uppssnewspub04.moswest.msn.net>...