 This is an old version – click here for latest version Since I have had a lot of problems with false positives with the black lists that I’m using on my Exchange 2003 server I started looking into another way of filtering spam. The obvious choice of additional protection fell on grey listing ( you can read more about what it is here ). The problem with this is that there doesn’t seem to be any free products out there for Exchange and as I don’t want to set up a Linux box ( yet another box in the rack ) I decided to write one myself. I don’t claim to be a world class programmer but my implementation seems to work just fine and that shows as I have a 98% block rate on incoming traffic. Usually i receive 3500-4000 spam attempts per day so that means that 70 mails a day are slipping trough. These 70 get matched to a blacklist that is not that aggressive and the result of this is that my spam level has gone down to almost 0% while I haven’t had a single false positive yet. |
About the program. It consists of two parts.
Requirements:
Features:
Greylist
Greylist admin
This is an old version – click here for latest version
| Install package | Greylist_v1.0.zip |
| Documentation | Readme.doc |
| Source Greylist | Greylist_v1.0_vs.net_source.zip |
| Source Greylist admin | GreylistAdmin_v1.0_vs.net_source.zip |
What does it cost?
Nada. Nothing. It’s for free!
See it as a contribution to a better world 
A free contribution! I’ve released this under a Creative Commonce license, which comes down to that you can use it and redistribute it as long as you refer to me and this site while using any part of my program. The full license is available in the readme file.
The program is distributed ‘as-is’ and I don’t intend to provide any support for it.
But feel free to send me any suggestions to improvements or your own modifications.
Cheers,
Chris
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September 28th, 2006 at 9:05
Oh I See i get a mention for the bullclip thingy which was just a passing comment and no mention for the hours of Interuption to explain program Flow. *?%%ing Network administrators. 😉
No actually this is a rather good building block look forward to tedious hours explaining encapsulation in Version 2.0
October 11th, 2006 at 2:00
This thing is fantastic. I was struggling with configuring an upstream Postfix-based greylisting SMTP server for my small Exchange server environment, but I found this and it works exactly as advertised. Thanks so much for your contribution.
October 13th, 2006 at 3:06
Great tool, one remark: Our production platform sends mail via SMTP through our Exchange server.
The tool we use for this doesn’t retry, so all mail is stamped as spam. Whitelisting was the only option.
October 13th, 2006 at 3:27
Hi
Great tool!
Could you make it work with Microsoft POP3 Services or does anyone know of any free anti-spam/greylisting?
(http://www.windowsnetworking.com/articles_tutorials/Windows_POP3_Service.html)
October 13th, 2006 at 5:58
Henrik: You could definetly write a greylist filter for the standard smtp service that comes with 200x, but it lacks some functionality that I’m using in my implementation.
So, the way it’s written today it will only work if you’re using Exchange.
Jeroen: What you did is completely right. As default it won’t make a difference between the inside or the outside so you need to whitelist any servers on the inside.
Cheers,
Chris
October 13th, 2006 at 7:44
Hi Chris
Yes! It seems to work with Microsoft POP3 Services
October 16th, 2006 at 5:24
Yet another version Here for IIS smtp.
http://attiliodrei.no-ip.com/greylisting/
October 18th, 2006 at 15:42
Will future versions allow wildcarding inside the whitelist? Tried whitelising 63.23.195.*, but doesn’t seem to work.
Thanks for making a wonderful piece of software!!!
with best regards,
Chuck
October 19th, 2006 at 2:36
Chuck: Yes definetly. I miss it myself too.
October 19th, 2006 at 6:55
Works great! Nice tool!!
October 21st, 2006 at 8:42
How can you remove this completely? After running “disable” there are four files I cannot delete.
October 21st, 2006 at 10:17
I’ve rebooted the server and was able to remove it completely. Ended up not being able to use it. After three days our table had over 14k records and stopped processing emails to Exchange. The admin app did report errors with my whitelist IP and email address inputs (note: I put in IPs just like in the readme – xxx.xxx.xxx.xxx format), but was working fine the day before. If you have some ideas or things to try, I would love to hear about it!
with best regards,
Chuck
October 23rd, 2006 at 14:26
Hi Chris,
First of all I would like to thank you for this very nice tool, It’s great for our small office of about 15 users.
One thing I was wondering was is it possible to have the greylist execute after our connection and recipient filtering in exchange?
I’ve looked over most of the property sheets in Exchange Admin and can not see how or if this is possible.
The issue is looking at the log and database I can see that a very large percent of the messages would be blocked
by connection and recipient filtering, the main reason I am concerned is that after only 3 hours of greylisting
my database has over 500 rows and is growing rapidly.
Thanks again for a great tool
Allen
October 24th, 2006 at 0:12
Well, this seems a great tool. Certainly stopped most spam cold. Only problem is I seem to be getting an error whenever I enter a whitelist item (Ip or email)
The error “Failed to enable constraints. One or more rows contain values violatiing non-null, unique or foreign-key restraints”
I cleared out the list and reentered them carefully but it still does it. Seems to still work and seems to recognise the whitelist
Nice job
Regards
Ian
October 24th, 2006 at 2:22
Allen: Yes you can do this by changin the source priority to a higher value in the enable.cmd script. It’s set to 77 as default which means that it will execute before all other filters. You can use enum.cmd to see where it is in relation to the other filters.
I wouldn’t recommend it though!! The reason for you getting 500 entries in three hours is because the greylist is working. This is normal. I get 3500-5000 new entries in my database daily and this continous flow of spam was the reason for me to write Greylist in the first place.
Cheers,
Chris
October 24th, 2006 at 9:45
Great tool …
I have a problem though. Even If i put my backend server in the white list it seems like I have problems sending mail, all outgoing mail queuing up on the backend.
Any ides?
October 24th, 2006 at 12:50
Thanks Chris
Allen
October 25th, 2006 at 1:40
Great tool
I also have a problem. It seems that the SPAM is stopped but now it
seems like I have problems sending mail trough my frontend server, all outgoing mail queuing up on the exchange
October 25th, 2006 at 2:51
My programming skills are not that good so is it possible to extent the program with an option to move spam to the junk folder of exchange or to specify a folder (within the public folders) for example. My clients complain that some email is missing.
October 25th, 2006 at 5:27
Finn: Try to add all sending servers to the source ip whitelist.
Cheers,
Chris
October 25th, 2006 at 5:52
It works – Thanks
October 25th, 2006 at 12:40
Hi Chris
I still try this great tool out and trying to fix et work on MS POP3 service.
For now I use it on an Exchange server, but get this web enabled:
abc.com #5.5.0 smtp;554 : Relay access denied
When disable, mail get in my mailbox, but SPAM do to then
Henrik
October 26th, 2006 at 11:26
Hi Chris,
I am trying to make some slight changes to the app and ran into a snag when it came to setting up the debugger environment.
Can you give me any tips on how you did this?
Thanks
Allen
October 27th, 2006 at 3:54
Allen: Have a look at http://msdn2.microsoft.com/en-us/library/ms998610.aspx#writingmngsinks_topic4
That describes very well how to debug event sinks.
Cheers,
Chris
January 3rd, 2007 at 8:39
Hi Chris, I am using MS SBS2003 with SP2 on Microsoft Exchange 2003. I would like to ask you if there is no problem with using your products Greylist on MS Exchange 2003 with SP2?
Super tool!
Thanks,
Martin