3 ms·

How do you deal with the spam issue?

by ktRolster 9y ago

gardnr 9y ago
For sending or receiving?
- ktRolster 9y ago
  How do you avoid receiving spam messages?
  - gardnr 9y ago
    I can't claim to be an expert in this field because I gave up years ago. Back when I was actively trying to prevent spam from entering my mail servers I would use: * Fail if no SPF record * Fail if DKIM record present in NS & not-present in message * blacklists (DNSBL) * heuristics (SpamAssassin) Back then, not everyone published both SPF and DKIM. I would only fail a message if it did have a DKIM record and the message did not have the matching DKIM header. If I recall correctly, I failed everything that didn't publish an SPF record. Blacklists are tricky because they are outside of your control. You are relying on a community of folks to tell you what is best. They are still extremely useful but use them with caution. Heuristics need to plug in to your mail clients' "Mark as Spam" feature. There has to be a feedback mechanism. There are a number of other configuration settings that control what can and cannot get through like requiring reverse DNS to accurately resolve sender ip = domain name. It is a wicked problem and a game of whack-a-mole. I found it better to pay dedicated experts to handle it.
SwellJoe 9y ago
SpamAssassin, greylisting with postgrey, DKIM/SPF checking in SpamAssassin (though DKIM is still configured to be somewhat forgiving). My email address has not changed in 12+ years and is widely available on the internet, and I get maybe a half dozen spam messages that make it to my inbox each day. That's more than I'd like, and slightly more than my GMail address receives. But, it's tolerable. I could probably tweak it a bit more to prevent more spam, but I don't really have time to micromanage it...I just let the filters do their thing. If I enforced DKIM I'd probably successfully block nearly everything, but I'd get a lot of false positives, too. A surprisingly large amount (like 5%) of the spam I get that successfully makes it through is not mass-email. It's people who have acquired a list of Y Combinator company founders and are sending out semi-personalized mail. A surprising amount of my spam mail name drops Y Combinator (and tries to imply they're already working with other YC companies). Which is really the weirdest damned thing, but it happens a couple times a week. But, I don't know that any spam filter could stop that. I get the same kind of thing (not YC related, usually, but things like recruiter emails) on my GMail account which is what I use in some developer communities.

How do you deal with the spam issue?

gardnr 9y ago

For sending or receiving?

ktRolster 9y ago
How do you avoid receiving spam messages?
- gardnr 9y ago
  I can't claim to be an expert in this field because I gave up years ago. Back when I was actively trying to prevent spam from entering my mail servers I would use: * Fail if no SPF record * Fail if DKIM record present in NS & not-present in message * blacklists (DNSBL) * heuristics (SpamAssassin) Back then, not everyone published both SPF and DKIM. I would only fail a message if it did have a DKIM record and the message did not have the matching DKIM header. If I recall correctly, I failed everything that didn't publish an SPF record. Blacklists are tricky because they are outside of your control. You are relying on a community of folks to tell you what is best. They are still extremely useful but use them with caution. Heuristics need to plug in to your mail clients' "Mark as Spam" feature. There has to be a feedback mechanism. There are a number of other configuration settings that control what can and cannot get through like requiring reverse DNS to accurately resolve sender ip = domain name. It is a wicked problem and a game of whack-a-mole. I found it better to pay dedicated experts to handle it.

SwellJoe 9y ago

SpamAssassin, greylisting with postgrey, DKIM/SPF checking in SpamAssassin (though DKIM is still configured to be somewhat forgiving). My email address has not changed in 12+ years and is widely available on the internet, and I get maybe a half dozen spam messages that make it to my inbox each day. That's more than I'd like, and slightly more than my GMail address receives. But, it's tolerable. I could probably tweak it a bit more to prevent more spam, but I don't really have time to micromanage it...I just let the filters do their thing. If I enforced DKIM I'd probably successfully block nearly everything, but I'd get a lot of false positives, too. A surprisingly large amount (like 5%) of the spam I get that successfully makes it through is not mass-email. It's people who have acquired a list of Y Combinator company founders and are sending out semi-personalized mail. A surprising amount of my spam mail name drops Y Combinator (and tries to imply they're already working with other YC companies). Which is really the weirdest damned thing, but it happens a couple times a week. But, I don't know that any spam filter could stop that. I get the same kind of thing (not YC related, usually, but things like recruiter emails) on my GMail account which is what I use in some developer communities.