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Are You Greylisting? — 8 Comments

  1. Effective greylisting really depends on the other mail server properly implementing timeouts and retries.

    One of my new correspondents was taken aback that his mail hadn’t been delivered. I checked my logs, and it had been deferred by the greylister. Unfortunately, his system didn’t retry again for another week! Of course, his complaint was that my anti-spam was too aggressive, but methinks his mail server was a bit too passive…


  2. Hi Bob,

    Yes, this is very true, and of course if someone’s mail server isn’t configures properly for their timeouts and retries, they also might not be configured properly for reverse DNS. However, I think there comes a point where we must put the onus on the sending server. As I said, I DID have to whitelist one server in the past year to avoid greylisting issues. That said, the post office is unlikely to deliver mail that is misaddressed or has no postage on it.


  3. This is what the Deep Six spam filter appliance does. When it doubts, it says wait, then send again to the offending mailer. Spam mailers never send again and in this way the Deep Six box stops all spam but lets the regular mail get through.


    You can put this box in front of your Groupwise box. It is a nice solution for people who are not able to build something themselves with Linux.

  4. If you’re not familiar or comfortable with Linux, there is a Windows solution that is free, providing you have Windows. There is a product called SmarterMail. It runs on Windows and will provide a full mail solution if you want or you can just use it as an MX or relay host. It allows for grey-listing, spf testing and several other anti-spam measures. We’ve been using this for several years and our results are just like yours. In that entire time I’ve had to white list 1 ip address due to a misconfigured mail server on the other end but it was the CEO’s personal accountant.

  5. Hello Danita,

    I have gone to your chats at Brainshare for many years, I currently have a Groupwise 7.0.3 installed on my NOWSSBE2 and it works great, but recently I have getting 550 errors on some emails and in yahoo it gets but into bulk, that´s right my Groupwise 7.0.3. I think the issue is greylisting…

  6. gwclient.conf

    change needed to AllowOverrides None to AllowOverride None. The former will throw an error when restarting Apache.