Bug with greylisting?

I know mail-in-a-box uses greylisting, how long are emails from unknown senders supposed to be bounced? I run a forum which sends mail through mailgun, checking the send logs via mailgun it shows that any emails sent to my box are bounced which then mailgun will re-try again in 5 minutes, 10 minutes, 30, 60 etc… But then the emails are dropped because my box still is not accepting emails from my forum domain/mailgun.

Is this a bug? I thought greylisting is supposed to only bounce email for the first 10 minutes rather than the entire day.


Do you have the SPF record configured correctly to allow mail sending from both your box and mailgun?

You might find this tool handy for troubleshooting:
Go through each section top to bottom, and at the bottom, you should be able to imitate your setup with mails coming from maligun. If this utility identifies an issue, your setup probably needs changing.

Oh no sorry.

I’m using mail-in-a-box for my personal email, I cannot receive emails from my forum that uses Mailgun.

The box is correctly setup with SPF, DKIM etc… So is the domain I’m using with Mailgun.

Checking the mail logs via terminal, I’ve just realised probably isn’t because of greylisting.

This is the error message in Mailgun.

bounce+28f2a8.e0241b-removed=removed.co.uk@mg.removed.org: Sender address rejected: Domain not found”,"

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I understand better now. Your box, where your personal email is held, is bouncing email that your forum generates (and sends via mailgun).

This seems to me like your forum domain, maligun, and SPF records perhaps for those 2 are not configured correctly. The box configures itself so as long as you don’t change anything, generally it is correct (assuming glue records, DNS setup follow the instructions).

You might try that same tool I mentioned though with some of your forum domain and mailgun settings?

SPF records for both my personal email and forum email are correct.

I’ve pasted the error message I receive from Mailgun above, seems that it may be a Mailgun issue… I’ll try sending through Postmark to see if I have the same issue.

Do you have an A record setup so that mg.example.org (or whatever your forum domain is) resolves okay?

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Ha. That worked… Has never been an issue with other email providers… Thank you :slight_smile:

I hate to think how many forum users have not received emails because of no A records on that domain :confounded:

Would there be a reason Google/Microsoft would accept emails from an address without an A record? Curious.

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Every mail provider (including the big ones) have their own setups and rules, some of which (Microsoft domains) are very confusing!

The tools provided with MIAB are very powerful and configured well. This means when the sending server is not configured correctly, that MIAB will be suspicious.

I find that MIAB does a tremendous job, much better than Gmail for example, of identifying spam and suspicious emails.

I’m glad the fix was straightforward and you’ve got it sorted.

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I see…

I’m really happy with mail-in-a-box, feels pretty great to have complete control of your own email without dealing with major headaches. Love it.

Thanks for your help :slight_smile:

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