Does SMTP greylisting a) stop much spam and also b) stop a lot reputable mail?

I've simply set up an SMTP web server on a reasonably little previously owned domain name making use of Postfix and also made it possible for greylisting with SQLGrey. Until now it appears to be functioning OK, and also while there's the mild irritability of hold-ups to e-mails from new senders, I can see from the logs that it's hindering a variety of spam messages.

In your experience does greylisting properly stop much spam? Is it a valuable enhancement to e.g. SpamAssassin or is including it ahead overkill/unnecessary?

If I were to roll this bent on larger usage domain names (probably with even more requiring customers) would certainly you prepare for a substantial section of inadequately set up mail web servers that would certainly wind up jumping or shedding messages?

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2019-05-07 08:16:32
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Answers: 5

I've had superb good luck with greylisting. Directly, I would certainly never ever utilize it as my only anti - spam action, yet when consisted of as component of a split anti - spam system (consisting of SpamAssassing, amavisd, clamav, RBLs, SPF/DKIM, etc), it gives a great deal of advantage.

One vital note, there are a couple of ISP is around (significant ones) that do not take care of a greylisted location beautifully (yahoo newsletter have actually been a popular instance). I would certainly suggest considering several of the whitelists that individuals have actually created to see to it that you do not wind up obstructing actual e - mail.

In my experience, the substantial bulk of e - mail that you get individual - to - individual (from an actual person/user) moves via among the significant mail web servers (postfix, qmail, exchange, sendmail), every one of which take care of greylisting effectively. Periodically you could find some newsletter software program or automated e - mail program that does not manage it appropriately, yet my experience recommends this is really uncommon.

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2019-06-01 02:54:49
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In your experience does greylisting properly stop much spam?

It is really reliable. I've utilized it for 3+years and also it has had a precise influence on our purification procedure.

Is it a valuable enhancement to as an example SpamAssassin or is including it ahead overkill/unnecessary?

It will in fact lower your scanning work. I advise including it.

If I were to roll this bent on larger usage domain names (probably with even more requiring customers) would certainly you prepare for a substantial section of inadequately set up mail web servers that would certainly wind up jumping or shedding messages?

I have actually seen this take place, although the mail web servers were drastically malconfigured (the postmaster had actually determined to quickly surrender on distribution if there was a soft mistake, as opposed to retry sending out). This comes down to just how the sender takes care of a 4xx vs. a 5xx message. If they treat them the very same, you'll have a couple of concerns. If they treat them appropriately , where 4xx is a soft - fall short and also the sender will certainly retry, there will certainly be no worry. Also if they have it malconfigured, the very easy remedy is to add the sender is domain name to your greylist as "currently seen", and also offering it a silly rating to maintain it from diminishing the data source.

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2019-05-31 23:48:02
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One feasible trouble with greylisting is that customers will certainly not get mails immediatly. This is most irritating for password reset mails. These mails generally get captured in greylist due to the fact that the sender/receipient/ip will certainly be new.

raj

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2019-05-30 09:15:41
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Yes, greylisting can stop a practical quantity of spam, really reasonably. Also when it does not stop spam, the included hold-up offers added time for the message or sender to be detailed on DNSBL or hash - based checklists.

You need to make certain that you make use of an excellent execution (I'm not directly accustomed to SQLGrey). Specifically, you can usually identify means to rely on triplets without having actually seen the specific triplet prior to (as an example if you've seen sufficient excellent triplets from an IP, after that there is possibly no factor greylisting any kind of more triplets from that IP). After a percentage of time, really couple of reputable messages are greylisted.

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2019-05-11 22:16:30
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In my experience, greylisting does not supply adequate advantage to warrant the downsides. While I had actually greylisting set up on my web server, it was frustrating sufficient to have every (new) inbound email postponed. I additionally recognize for particular that some inbound email was obtaining shed.

Spammers were relentless adequate (and also I assume also back after that they were beginning to instantly do retries) that their spam survived anyhow. I transformed greylisting off years earlier and also have not recalled.

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2019-05-09 03:34:20
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