Exchange Server email filtering

[Farelf]

We usually talk just about "ISP" and "user" filtering. A great many corporate users use MS Exchange and associated products. The following is a synopsis (with further links) of the state of play concerning email filtering in such an environment. Six layers, no less. Well, many would use less than six layers actually but ... I am faintly amazed anything gets anywhere anytime without (instead) meeting a silent death:

http://searchexchange.techtarget.com/generic/0,295582,sid43_gci1301525,00.html

So, the reasons for occasionally delayed delivery etc. are not too hard to understand when the path of a message through such a mill is considered. Note there is an advantage in using Outlook to mail a recipient in some cases (which probably include many/most of the major corporates).

All necessary because of the spammers (emitting 95% + of message volume). The most complicated and costly "band-aid" in the history of communications technology and process. I wonder how many tons of CO₂ a day that all adds up to? And getting worse each day. Most of populace is unbothered - not unlike boiled frogs, I guess.

[rconner]

The following is a synopsis (with further links) of the state of play concerning email filtering in such an environment. Six layers, no less.

Seems rather excessively complicated to me, like a lot of other common technologies that MS gets its hooks into. I've spent the last week in testing a system we are delivering, and fortunately have not had to have much to do with the MS security issues, which seem pretty Byzantine to me. I am smart enough to recognize that some of this complication serves a useful purpose, but a lot of it seem superfluous to me. Can't deny that it seems incumbent on MS to "proprietize" (if that is a word) its technologies to keep customers dependent.

I don't know how much mail gets exchanged over the public network via MS Exchange directly. I know that Exchange is designed to allow Exchange-to-Exchange transfers over the backbone, but I generally do not see this in my office e-mail except for my company's "intramural" mail, and NOT in mailings between two distinct Exchange shops (i.e., two different companies both using Exchange). I think that most of these are done using SMTP gateways built into Exchange. This being the case, it seems like Exchange shops could make use of the same sorts of filtering used by ISPs (i.e., dedicated mail filter boxes).

-- rick

[Farelf]

... seems like Exchange shops could make use of the same sorts of filtering used by ISPs (i.e., dedicated mail filter boxes).

Too simple Rick, y'gotta have edge transport servers and hub servers and ... my brain hurts.

... Can't deny that it seems incumbent on MS to "proprietize" (if that is a word) its technologies to keep customers dependent. ...

Proprietrisation surely is a cunning stunt (exercising enormous restraint by going no further with that one) and whereas the path to untold wealth was once something like becoming the personal dental hygienist (or "dentist" in the quaint oldspeak) to the Osmond family it is now clearly directed towards supercity (Brian W. Aldiss's "easy way to the top", making yourself indispensible by being a little bit, and carefully, useless). Vague recollections of capabilities that used to be native in Outlook now requiring Exchange - sharing/synching contacts maybe.

[Telarin]

Wow, talk about making a relatively simple process seem extremely complicated. I run an Exchange Server here, and use DNS blocklisting and IMF for filtering, and that is it. It removes somewhere on the order of 99.9 to 99.99% of incoming spam without any problems. Single server, no edge servers etc. Of course, if you want to server 10000 users instead of 50 or 60, then the extra complexity becomes a necessity just to handle the loads, but for the average small shop, exchange is easy to setup and maintain.

[Farelf]

...but for the average small shop, exchange is easy to setup and maintain.

Thank goodness for that - thanks Will, confirms my guess "Well, many would use less than six layers actually but ..." At work we have a (very) small shop, inwards mail is silently "handled" by ISP (nobody knows what happens there but a - supposedly - small amount of goodmail doesn't make it through from what is "obvious"), client level filtering in Outlook doesn't work (something to do with the way Exchange is set up so I guess client level filtering would be redundant, don't know) but at the end of the day most client accounts typically receive only 0-6 spam a day. The ISP action makes it all problematical but if we turn that off we would presumably have to step up our filtering which now sounds like it is not such a huge thing. Thus far the execs are happy with whatever it is they don't know about in terms of lost mail so the point is moot right now. First step if it goes further would be to find out what happens to stuff Exchange may or may not be handling - hopefully someone in our org can find. I worry too much.

But the huge effort for a top-of-the-range solution certainly caught my attention.