Is there a way to turn Greylisting on during certain times?

Question asked by Patrick Mattson - 10/28/2019 at 5:15 PM

Answered

I have run into issues with having Greylisting on during standard business hours. Emailer A would send from IP 1.1.1.1, when it retries a minute later they now send from 1.1.1.2. I had some upset customers not receiving emails, so I had to turn it off. The biggest complaint came from password resets or needing a code.

If I could turn it on during my evening hours and/or weekends I may cut down on spam in their inbox. This might be helpful in an event of an outbreak overnight.

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Alex Clarke Replied

10/29/2019 at 1:28 AM

I don’t think you can do this via the SM interface, but maybe you could write a script to edit the relevant settings file and then run this on a scheduled task.

While the above would work, I’m sure that it’s not considered “best practice” and ST may even say it could corrupt your settings file (writing to this as the same time SM does).

I’ve already proposed to ST that the greylisting code should be improved and this has been logged as a feature request.

We suffer from issues with emails from btinternet.com mailboxes a lot. The email will be sent from a server on this domain (i.e. mail1.btinternet.com) and be rejected. It will then be sent from mail2.btinternet.com and also be rejected.

Only if the email is sent from the first server again will it make it to the recipient.

I’ve requested that ST change the way greylisting works to treat multiple servers on one domain as a single entity. This would have to be verified by rDNS/PTR records - to avoid spoofing.

The above idea would solve a lot of problems.

Sébastien Riccio Replied

10/29/2019 at 10:33 PM

You could probably schedule a task to a script that will use the API to toggle greylisting on and off at a certain time.

I think it can be done at system wide level, per domain and per user.

For example at domain level:

https://mail.smartertools.com/Documentation/api#/reference/SmarterMail.Web.Controllers.Api.DomainSettingsController/SetDomainSettings

There is a field

"bypassGreyListing": boolean,

I did not try it but it should work.

Sébastien Riccio System & Network Admin https://swisscenter.com

Bruce Replied

10/30/2019 at 4:29 AM

Marked As Answer

How I get around this and delays and blocks in emails from legitimate sources is to set the 'Grey Listing Threshold' to 10 in the Antispam, SMTP Blocking Settings.

This way only email which has a spam score of 10 or above is greylisted, so emails from legitimate sources like Btinternet are delivered without the greylisting delay or problems with changes in the IP that sent the email.

Alex Clarke Replied

10/30/2019 at 5:41 AM

That's a good idea Bruce! Thanks for sharing.

Bruce Replied

10/30/2019 at 6:03 AM

You are welcome

Patrick Mattson Replied

10/30/2019 at 2:56 PM

Bruce, thanks for the input, I implemented that this morning. So far not a lot of Greylistings, but a few so it must be working.

Derek Curtis Replied

10/31/2019 at 10:56 AM

Employee Post

I changed this Thread to a Question, and marked Bruce's reply as the answer.

That's because there isn't a way to set a "time of day" limit on greylisting, and Bruce's answer seems the simplest thing to do within the interface to achieve at least similar results.

Derek Curtis COO SmarterTools Inc. www.smartertools.com

Nathan Replied

11/1/2019 at 7:50 AM

Derek, would it be possible to change the greylisting so that it applies it say at a /24 rather than /32? This would somewhat mitigate the situation where retries come from different IPs in the same network. Perhaps have it as an option that could be toggled between /32, /24, /16 ?

Derek Curtis Replied

11/1/2019 at 8:02 AM

Employee Post

I'd have to ask about that, Nathan. If it IS something we'll entertain, it may be awhile as that's a pretty big change. Once we get MAPI out the door, we'll be planning future Builds and can look at suggestions.

In fact, you may want to take that and create a NEW Idea thread for it...

Derek Curtis COO SmarterTools Inc. www.smartertools.com

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