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The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

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Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#11

Post by [deleted] »

dmm wrote: post #10
kazinator wrote: post #8

Earlier quoted context omitted.

Resolving MX records from your home and contacting hosts directly on their port 25 is a nonstarter. I wouldn't even think of doing it. Instead, I forward to my ISP's SMTP forwarding hosts (via an authenticated SMTP connection). It's not necessarily the "working DNS" rule that will reject you, but other methods, like anti-spam databases that list residential line IP addresses. For example, my residential line, in fact…

> Resolving MX records from your home and contacting hosts directly on their port 25 is a nonstarter. Google, Yahoo, and Microsoft accepted mail from my server without any issues. My server never sent spam and was never on spam blacklists. What's your problem? Maybe you suck.

[deleted]

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#12

Post by [deleted] »

dmm wrote: post #10
kazinator wrote: post #8

Earlier quoted context omitted.

Resolving MX records from your home and contacting hosts directly on their port 25 is a nonstarter. I wouldn't even think of doing it. Instead, I forward to my ISP's SMTP forwarding hosts (via an authenticated SMTP connection). It's not necessarily the "working DNS" rule that will reject you, but other methods, like anti-spam databases that list residential line IP addresses. For example, my residential line, in fact…

> Resolving MX records from your home and contacting hosts directly on their port 25 is a nonstarter. Google, Yahoo, and Microsoft accepted mail from my server without any issues. My server never sent spam and was never on spam blacklists. What's your problem? Maybe you suck.

[deleted]

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#13

Post by dang »

dmm wrote: post #6

You suck! I ran an email server from my home for several years. I could get a static ip but my isp wouldn't set my rdns for some reason. I had both spf and dkim correctly configured but people like you eventually forced me to move to commercial hosting.

Personal attacks are not allowed on Hacker News. We ban accounts that do this, so please don't do it again, even at someone you feel is unskilled at setting up a mail server.

We detached this subthread from https://news.ycombinator.com/item?id=12398943 and marked it off-topic.

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#14

Post by AstralStorm »

kazinator wrote: post #8
dmm wrote: post #6

You suck! I ran an email server from my home for several years. I could get a static ip but my isp wouldn't set my rdns for some reason. I had both spf and dkim correctly configured but people like you eventually forced me to move to commercial hosting.

Resolving MX records from your home and contacting hosts directly on their port 25 is a nonstarter. I wouldn't even think of doing it. Instead, I forward to my ISP's SMTP forwarding hosts (via an authenticated SMTP connection). It's not necessarily the "working DNS" rule that will reject you, but other methods, like anti-spam databases that list residential line IP addresses. For example, my residential line, in fact…

Funny thing, my own old mail servers allowed that for AUTHed SMTP w/ correct TLS, but then disallowed invalid domains or wrong account in From field.

There are really no legitimate reasons to allow spoofed outgoing mail.

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#15

Post by kazinator »

Nux wrote: post #9
kazinator wrote: post #3

One powerful rule that I use in my Exim setup is to drop any SMTP connection that doesn't have forward and backward DNS that match. This catches a big majority of all spam, with hardly any false positive downside. No credible in SMTP forwarding host has broken DNS (by definition, practically). Lots of spamming machines do. Of course, not all, but this is a game of percentages and multiple stages.

So, do you require the PTR and A records of the remote host to match?

I don't work with DNS at the protocol level; it's done via the Exim "verify = reverse_host_lookup". The documentation says:

This condition ensures that a verified host name has been looked up from the IP address of the client host. (This may have happened already if the host name was needed for checking a host list, or if the host matched host_lookup.) Verification ensures that the host name obtained from a reverse DNS lookup, or one of its aliases, does, when it is itself looked up in the DNS, yield the original IP address.

The phrase "or one of its aliases" seems to imply that the match does not strictly require the A record.

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#16

Post by Robin_Message »

The spam bit sounds cool but the nosql db sounds odd. E.G. That tree implementation with batched rebalancing sounds downright scary, and I thought avl was considered the worst kind of balanced tree due to excessive overhead (an int per node to red-black's bit) .

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#17

Post by [deleted] »

dang wrote: post #13
dmm wrote: post #6

You suck! I ran an email server from my home for several years. I could get a static ip but my isp wouldn't set my rdns for some reason. I had both spf and dkim correctly configured but people like you eventually forced me to move to commercial hosting.

Personal attacks are not allowed on Hacker News. We ban accounts that do this, so please don't do it again, even at someone you feel is unskilled at setting up a mail server. We detached this subthread from https://news.ycombinator.com/item?id=12398943 and marked it off-topic.

[deleted]

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#18

Post by ihuman »

dang wrote: post #13
dmm wrote: post #6

You suck! I ran an email server from my home for several years. I could get a static ip but my isp wouldn't set my rdns for some reason. I had both spf and dkim correctly configured but people like you eventually forced me to move to commercial hosting.

Personal attacks are not allowed on Hacker News. We ban accounts that do this, so please don't do it again, even at someone you feel is unskilled at setting up a mail server. We detached this subthread from https://news.ycombinator.com/item?id=12398943 and marked it off-topic.

I understand why this comment was deleted, but how come it was detached and made into a top-level thread? I'm not against it or anything (if I sound like I am), I just don't see anything in the rules or FAQ about it, so I was curious.

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#19

Post by dang »

ihuman wrote: post #18
dang wrote: post #13

Earlier quoted context omitted.

Personal attacks are not allowed on Hacker News. We ban accounts that do this, so please don't do it again, even at someone you feel is unskilled at setting up a mail server. We detached this subthread from https://news.ycombinator.com/item?id=12398943 and marked it off-topic.

I understand why this comment was deleted, but how come it was detached and made into a top-level thread? I'm not against it or anything (if I sound like I am), I just don't see anything in the rules or FAQ about it, so I was curious.

We do that because then we can mark the subthread off-topic, putting it much lower on the page. If we didn't detach it first, marking off-topic would only put it lower among its siblings.

This originated as a technique for dealing with "topjacking", i.e. comments that are posted as a reply to the top comment, not because they're relevant replies but simply to be nearer the top of the page. Later, we realized it was useful to demote subthreads where people were breaking the HN guidelines.

When we do this, we nearly always post a comment explaining that we did it. For mind-numbingly boring reading, see https://hn.algolia.com/?sort=byDate&prefix&page=0&dateRange=... and https://hn.algolia.com/?sort=byDate&prefix&page=0&dateRange=....

Re: The Cat-And-Mouse Story of Implementing Anti-Spam for Mail.ru

#20

Post by Normal_gaussian »

dang wrote: post #19
ihuman wrote: post #18

Earlier quoted context omitted.

I understand why this comment was deleted, but how come it was detached and made into a top-level thread? I'm not against it or anything (if I sound like I am), I just don't see anything in the rules or FAQ about it, so I was curious.

We do that because then we can mark the subthread off-topic, putting it much lower on the page. If we didn't detach it first, marking off-topic would only put it lower among its siblings. This originated as a technique for dealing with "topjacking", i.e. comments that are posted as a reply to the top comment, not because they're relevant replies but simply to be nearer the top of the page. Later, we realized it was u…

Those may only be mind numbing for you who have to go through it every day, I really enjoyed the first two pages. Couldn't imagine having to do the replies though - a suprisingly large number had been customised!
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