Genii Weblog

Why not use Exchange Connector instead of CoexLinks

Wed 25 Feb 2004, 10:07 AM



by Ben Langhinrichs
I'll write this up as a position paper, but I just had to get it off my chest...

When people evaluate CoexLinks, they often ask the question, "Why can't we just use the Exchange Connector?  It does the same thing."

There are three answers, and I am never sure which to give first.  Here are the three answers, and you tell me which is most compelling:

Exchange Connector is Not Supported
This may seem a pretty blanket assertion, but the following three Microsoft technotes pretty much describe the story:

XFOR: Exchange 5.5 SP2 Notes Connector Does Not Currently Support Lotus Notes R5 Server (documents the lack of support for  Exchange 5.5 SP2, the most common configuration of Exchange 5.5. and Notes/Domino R5.x)

XCON: Microsoft Support Policy for Exchange Server Coexistence with and Migration from Lotus Notes/Domino 6.x  (documents the lack of support for  Exchange 2000 and Exchange 2003 with Notes/Domino R6.x)

XFOR: Lotus Notes Client Versions That Are Tested with the Exchange Notes Connector (documents that even in an unsupported, use at your own risk configuration, the last version of Notes they even tried out was Notes 5.0.10.  Since ND6 isn't supported at all as described above, this is not likely to change.)

Exchange Connector is Architecturally Weak Solution
This is also a fairly broad assertion, but it is not one Microsoft would likely argue with.  They built the Exchange Connector as a way to bridge the gap while people moved to Exchange.  Since few people are moving that way these days, they have abandoned the effort.  In any case, here are just a few of the myriad design problems:

1) Requires an R4 client running on an Exchange server.  The Exchange Connector requires an R4 client, yup R4 (see this technote and search for "4.62") running on the Exchange server.  So, an unsupported version of Notes running as client software on a server is the basis for this product.  There are many by-products of this poor design, not the least is this technote:

XFOR: Exchange Notes Connector Does Not Send HTML (documents the issue that if any user has their mail set to go out as MIME, the e-mails will simply be discarded, which is not surprising, since R4 didn't support MIME in messages)

2) Single point of failure.  The Exchange Connector must be set up so that all mail travels through one connector on a single Exchange server.  There is no provision for load balancing, different routing based on MIME e-mails, or anything else that would allow a larger organization, or a smaller one with diverse needs, to split up the mail.  If the rickety Exchange 5.5 server (only version supported) fails, all your mail routing stops.

3) Too many links in on document cause crashes .  The Exchange Connector must be set up so that all mail travels through one connector on a single Exchange server.  There is no provision for load balancing, different routing based on MIME e-mails, or anything else that would allow a larger organization, or a smaller one with diverse needs, to split up the mail.  If the rickety Exchange 5.5 server (only version supported) fails, all your mail routing stops.

Besides this, take a look at Microsoft technotes documenting many other issues: 253712, 245569, 181742, 253029, etc.

Exchange Connector Provides Very Little Flexibility Compared to CoexLinks
The Exchange Connector solves, or tries rather badly to solve, I should say, one problem in one way.  When it works correctly, it replaces doclinks with NDL attachments.  It does not accurately mark where the original link was, so if there were multiple links, a person may click on the wrong NDL link.  It does not provide disclaimer support so that recipients may not know why there is an indication that there is a link, but there is only an attachment.  It does not provide the ability to create Notes URL links.  It does not provide the ability to create Web URL links in case the Notes client is not available and a web interface has been added.  It does not allow limitation of the number of attachments for mail systems that limit attachments.

I could go on and on, but I'll save it for the white paper.  Let me know if you want to see more, and I'll happily provide an early copy before it is posted.

Copyright © 2004 Genii Software Ltd.

What has been said:


122.1. Chris Miller (03/01/2004 10:22 AM)

Well wait though. Anyone we migrate we definitely tell them to apply the recent SP to Exchange 5.5 for the server we are connecting to. This lets us run the 5.x client. No where have we ever had to still run a 4.x codebase on the server as it was back in the early migration war days. Also, you do not need a Notes 6 client as the one technote states since moving the data has no bearing if you are rolling out the Domino 6 server on your side compared to what integration version you run on that server. Mainly since Notes 5.x clients are supported interacting with the Domino 6 codestream right?

Now don't get me wrong, I think there is tons wrong with the product overall mainly when Lotus wants you to migrate them over. Single point of failure being one huge effort. We have had to restart the connector since sometimes it just 'falls asleep' on us and wakes up on restart. I wish there was more functionality and not so many potholes, but most clients wont invest in some of the thrid party products we have seen. No matter what you tell them they want what the Redbooks promote. A big circle if you ask me.