Miab delaying (or worse) legitimate emails from poorly setup email servers for ~24-48 hours

I frequently receive legitimate emails from people with poorly setup email servers, for instance today i know someone sent me an email from upmsolutions dot com.
From mxtoolbox i can see they have no dmarc record, maybe this is the issue?
They sent me a photo of the email they sent, and I believe they’re being honest about sending it, they have no reason to lie, also I’m pretty sure i’ve seen this issue before with other poorly setup email servers.

In the case of this email, they sent it maybe 3 hours ago, and I’ve still not received it.
Maybe i will get it eventually or maybe not, I’m not certain.
Sometimes I’ve noticed when I start the day that I have new emails in my inbox that I should have gotten a day or two before, they emails will be date stamped with the date a couple days before.

my miab server is using default settings for everything, and following all the recommended miab settings, including using miabs nameservers. All email based ports, are open.

I want to be able to see these emails when they are sent, without delay, without fear of the emails never arriving, if It means opening myself up to a little more spam, I’m ok with that. I cannot rely on people emailing me to have good servers, I’m mainly communicating with people in developing countries where apparently that’s a common issue. Can anyone offer me any suggestions?

I might have a few more specific suggestions if I had more precise information about your setup, but I’ll offer some basic suggestions of things I would try first.

  1. The most obivous thing you need to check is whether spamd is sending these emails to your junk folder. I don’t know if you use webmail only, or clients running POP3 or IMAP, so it’s hard to be more specific about this. For example, I run POP3 from my client, but POP only pops the inbox, so I have to log into the account on the server using webmail to check the junk folder, because if spamd sends an email to junk, it will never get pop’ped to my client.

  2. Dig through the server logs looking anything related to missing or delayed email. I’d suggest starting by searching for the sender address of any such email you’re expecting and try to see if there’s any useful information about how the server treated these emails.

  3. Look at the headers, especially the spam headers, of an email that arrived a day or two late to see how spamd scored the email. Maybe the headers can shed some light.

  4. postgrey (postfix greylist) is running on a mailinabox server. I’ll just quote what it does from an Ubuntu site:

    “Greylisting” is a spam reduction technique that can be very effective. It works by temporarily rejecting from client machines that are unknown to the server’s greylisting service.

    You might want to look at changing the settings for that. For example, to help cut down on delays, I’ve whitelisted the accounts I care most about because I don’t want to wait several minutes or more to get an email from a server that’s unknown to my server. That’s a personal decision with the cost that I’m more susceptible to spam on those account, but I didn’t want to wait many minutes for an email when a new service is sending me an email confirmation, for example.

    I imagine it would be possible that a poorly configured server might get a few rejections from postgray and then wait for a long period of time before retrying (or never retries again).

That’s all I can think of for now. Hope this helps.

Thank you, I can offer any information, I have complete control over the system.

  1. The emails are not going to the junk folder, I use thunderbird, But I checked both thunderbird and the webmail an hour ago, because i too was hoping they would be there. (I’ve never seen any differences in emails between the two, I’ve noticed this problem before and tried in the past as well). After the ~2 day delay the emails do tend to show up in the junk mail folder, (though i’m not sure it’s all of them, or that no emails are bounced or something else). I’m using imap.

  2. I’m not really clear how to check the logs, and i know miab uses a lot of services, so I’m not sure which logs i should be looking for?

3, I have looked at the headers, I don’t know about this email today, but I’ve noticed some weird things here in the past, where the time stamps show very long delays like an entire day between various servers. I can’t seem to find this example in the past (i thought it was a delay in their own server in that case) But I’ll be checking on this over the next couple days with this new email because I know exactly when it was sent, so I’ll have better information.

  1. I was thinking about this, i’ve seen other people talking about stuff like this and that your modifications can get overwritten when doing a miab update, has this been your experience? Any tips? I haven’t messed with postgrey/postfix before.

I appreciate your help!

You can whitelist recipients for postgrey and this file is not affected by upgrades. The file is /etc/postgrey/whitelist_recipients and will not be overwritten by MiaB updates.

For example, the first three lines of my file (after the comment header) is:

postmaster@
abuse@
john@

and this tells postgrey that this user at (@) any domain should skip the rejection step. You might just try adding your email address (or the part left of the @ symbol) to this file and see if that helps. If you change the file, I believe you’ll need to restart the service with something like sudo systemctl restart postgrey (just going by memory here but if in doubt then just reboot the server instead).

As for digging through logs, I’m not sure if I can help you here in this forum. It’ll require some experience on the *nix command line using tools such as grep to do that.

You can find multiple commands here to check the logs

Check delivery queue (about "Delayed Mail - still being retried") - #2 by eXTric

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