/dev/chat - 2022-01-30

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3:18 PM

@FaheemMitha perhaps it's because I run my own mailserver (yes, really) but the explanations further down the page seem quite reasonable. A DNS entry for a mail server is supposed to match its rDNS (and preferably its HELO too)

I've recently abandoned the requirement that there must be a valid "From: " header in incoming email. Mainly so I can get bills and other important information from my home energy supplier. They create invalid emails but trying to convince them of that fact is nigh on impossible

3:58 PM

@roaima That's very brave of you. How would you summarize the experience of running your own mail server?

@roaima Is this something that mailbox.org is using? And yes, convincing corporations of anything (or even finding someone who understands what I'm saying), is usually difficult, bordering on impossible. In fact, I can't off the top of my head think of a single success in that area.

Mostly good but increasingly frustrating.
- It was a mixture of SpamAssassin, Greylisting, Blackhole DNS, and adhering to SPF instructions from other domains.
- Unfortunately I've had to abandon Greylisting due to the growing number of organisations that don't understand temporary delivery failures (usually Enterprise software that's delivering email directly to targets on the Internet) *and* who use a different (machine generated) sender or machine address for each delivery attempt.
- SPF is a joke. Too many organisations either have "we don't care what we do" SPF declarations or else declare

@roaima Sounds headachey. Do you think the mailbox.org policies look reasonable. They do enable greylisting by default. And more generally, do you have any opinion about mailbox.org as an organization? Are they reasonable people to deal with?

I'm moving away from my current email host, Luxsci. They aren't cheap (at USD 10 a month). I've used them since 2011, and at that time they had excellent reviews, though I didn't save them at the time. These days it's hard to find any mention of them. They have somewhere between terrible and non-existent spam protection. The last straw is that they just increased their fees to USD 15.

4:13 PM

I don't know anything about mailbox.org as an organisation. Depending on how you want to use them you may need to disable Greylisting, but leave the remainder enabled. I would be inclined to allow Spam-flagged emails but redirect them to a Junk/Spam folder for occasional review. Given the number of important emails generated from applications I wouldn't discard immediately - but I wouldn't necessarily want to see them in my Inbox

They used to charge extra (USD 2) for a "custom" spam filter. No idea how good it was - I never tried it. It struck me a bit much to charge extra for spam protection.

I've just had a follow-on thought. You might find that Mailbox's greylisting is better than mine was, and it can cope with similar-but-different servers sending the same email

@roaima Yes, perhaps outright rejection is not be be the course, but in practice I ignore my spam folder.

For one thing, there is just too much stuff in it, and it's all garbage.

True, me too, except when I'm looking for the vital email the person on the phone assures me they've just sent...

@roaima So you've had no dealing with mailbox.org? I guess they're quite small.

@roaima Yes, ditto. Though most of the time it isn't there.

4:16 PM

Correct

@roaima Any opinion on how they look? They seem relatively technically minded as such orgs go. And I've done a little browsing on their site. The owner sounds reasonable.

He's written a bunch of stuff on the site. And there are various support emails and misc discussions scattered around.

@roaima If you have a minute, send me a test email at faheem@mailbox.org. I'm soliciting test emails from people to try to see how the spam filter copes. And if you send it, ping me here. And let me know if you want me to acknowledge it.

And preferably from an address that isn't gmail. I'm not sure why, but everyone seems to use that now.

Sent. An acknowledgement would be good, thank you

2022-01-30 16:21:49 1nECxW-0007n9-BV H=mx2.mailbox.org [80.241.60.215]: SMTP error from remote mail server after RCPT TO:<faheem@mailbox.org>: 450 4.2.0 <faheem@mailbox.org>: Recipient address rejected: Greylisted, see postgrey.schweikert.ch/help/mailbox.org.html

@roaima I thought greylisting was selectively applied. The Wikipedia page refers to unrecognised servers. I'm not sure what that means.

@roaima If I can figure out how to send an email from mailbox.org's web interface, I will.

I wonder if emails to my custom address can be sent to two actual different email addresses.

2022-01-30 16:27:21 1nECxW-0007n9-BV => faheem@mailbox.org R=dnslookup T=remote_smtp H=mx2.mailbox.org [80.241.60.215] X=TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256 CV=yes DN="CN=*.mailbox.org" K C="250 2.0.0 Ok: 8549 bytes queued as A2685A00C7"

@roaima That's success, I assume. Is the mailbox.org reporting back to your server?

I don't see such things. Is this because you're an admin.

Also

> Also, legitimate mail might not get delivered if the retry comes from a different IP address than the original attempt. When the source of an email is a server farm or goes out through some other kind of relay service, it is likely that a server other than the original one will make the next attempt. For network fault tolerance, their IPs can belong to completely unrelated address blocks, thereby defying the simple technique of identifying the most significant part of the address.

4:30 PM

Yes. It's my mailserver telling me that it successfully delivered the message to mailbox.org. It'll either be in your Inbox or your Junk/Spam now

> Since the IP addresses will be different, the recipient's server will fail to recognize that a series of attempts are related, and refuse each of them in turn. This can continue until the message ages out of the queue if the number of servers is large enough. This problem can partially be bypassed by proactively identifying as exceptions such server farms.

> Likewise, exception have to be configured for multihomed hosts and hosts using DHCP.[2] In the extreme case, a sender could (legitimately) use a different IPv6 address for each outbound SMTP connection.

I guess that's what you were talking about.

Yep. That's why I finally abandoned greylisting. Too many organisations now (reasonably) use server farms for mail delivery

@roaima I see. And you lean towards recommending I not use it as well?

I don't know how mailbox implements it, so I can't make a recommendation one way or the other. It worked for my email - but my mail server queues and retries on temporary failure (like it should)

@roaima But you just said you had issues with it. So it "worked" in what sense?

@roaima In summary, how effective are your anti-spam measures at keeping spam out? And you maintain mail servers for an organization, not just for yourself personally, right?

4:38 PM

I had issues with the implementation called "greylistd". It couldn't (can't?) handle server farms. It gets frustrating when you know you've got 15 minutes to enter the security codethat validates your email address but because the sender is using a server farm the message doesn't arrive for 25 minutes...

I think we're fairly effective still. We were more effective before, but I had to trade off against usability.

Professionally, we use Exchange Online - part of Office365 - with a third-party antispam service on the front end. That works really well and I rarely have to worry about it. But of course we pay for the service

@roaima So a particular implementation, not the general technique? I should search if mailbox.org has anything special to handle greylisting for server farms.

I attempted to reply, but got:

I saw that (just), thank you - did you see the "can't do that for unpaid accounts" message? So that's on your side

@roaima Yes, I saw it. Looks like I can't send email till I have a paid account.

Sorry, I deleted because I realised is was showing your name and email address.

I was going to repost a elided version, but I guess I don't need to, if you saw it.

I was planning to switch to the 3 Euro version, but haven't yet. Thought I'd try to see if there were any showstoppers first.

Give it a try. For €3 it's worth it

@roaima I expect I shall. Most of the other options don't look that good, as far as I can tell.

The only discussion of greylisting I've found from mailbox.org is userforum-en.mailbox.org/topic/disable-greylisting

The owner is Heinlein. He sounds reasonable, like I said already.

Peer Heinlein (* 11. Juni 1976 in Berlin) ist Fachbuchautor, Linux- und Sicherheitsberater und Unternehmer. == Biografie == === Schule, Studium und Abschlüsse === Heinlein besuchte bis 1995 das Georg-Herwegh-Gymnasium in Berlin und studierte daraufhin Rechtswissenschaft an der Humboldt-Universität zu Berlin. Sein Studium schloss er 2001 mit dem ersten Staatsexamen ab. Er ist als Linux-Administrator (LPIC-2) zertifiziert. === Autor und Redakteur === Ab November 1992 bis zum Juni 1998 war Heinlein bei der Jungen Presse Berlin ehrenamtlicher Mitarbeiter, darunter fünf Jahre als 1. Vorsit...

Among other things, he's written books on email software. So he's certainly qualified.

5:30 PM

@roaima Belatedly, an obvious question. If a server farm is trying to email me, and the greylisting keeps bouncing it, is there any way I would know it was happening?

Does this article from 2014 still describe the current state of affairs? sss.co.nz/news-and-updates/…

@roaima Is this Exchange Online thing an option for a single user?

6:06 PM

Yes it is - outlook.com is for personal users. You can use it for free as @outlook.com, or pay up and get a personalised domain on it. IMAP/SMTP for the email works well or you can use a web interface. I'm off for the evening now

We switched to mandatory outlook at the university last year or so. My favourite part is the junk filter that cannot be disabled, and which routinely bins important work-related emails. The junk filter runs before IMAP does, so you don't even get to see these false positives in an email reader. Excellent user experience.

When I looked this up I saw years-old threads complaining about the same thing. It's a known "feature".

6:53 PM

@AndrasDeak I assume that's sarcasm.

Is this Exchange Online a MS thing, by any chance?

@FaheemMitha correct

@FaheemMitha also correct

exchange as in microsoft exchange, hence outlook

OK, the complaint thread about the junk filter is only 2 years old answers.microsoft.com/en-us/outlook_com/forum/all/…

@AndrasDeak Eww.

Oh, this is hilarious i.stack.imgur.com/bXbmv.png

@FaheemMitha my magic 8-ball says "outlook not so good"

7:59 PM

This seems like an important question. Does anyone have an answer?

2 hours ago, by Faheem Mitha

@roaima Belatedly, an obvious question. If a server farm is trying to email me, and the greylisting keeps bouncing it, is there any way I would know it was happening?

For example, I can't whitelist a domain if I don't know it is trying to contact me.

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