I’ve been using MailInABox for a good few years now but never really for important stuff. Now however I need it to run like a proper mailing service and it just won’t.
I have set it up on a new clean VM using Ubuntu 18.04 and MIAB v0.43. Mails get sent and received all right, but every single big provider puts them in Junk/Spam. So I’ve started looking into it, first with MXToolBox then with MailTester and things were all over the place. In a few hours I’ve managed to fix SPF and DMARC but DKIM just won’t work.
My setup isn’t as straight forward and simple so I’m thinking maybe I’m doing something wrong at the DNS level rather than the DKIM config.
I have my main domain “herc.tech”. My mail server (MIAB) and its PTR are at “mail.srv.herc.tech”. All of my other domains have their MX DNS record set at priority 50 and hostname “mail.srv.herc.tech”. I’m using an external BIND DNS Server that I’m managing myself instead of the one provided by MIAB but I have copied all the records as they are shown on the “External DNS” page to no avail.
It’s now been two days that I’ve spent trying to get DKIM to validate properly and all I get is invalid signatures.
My questions are as follow:
Is it right that MIAB tells me to put the exact same DKIM record to all my domains? My “herc.eu” and “herc.tech” and “herc.me” are all supposed to have the same “mail._domainkey.” entries based on the “External DNS” page.
Is there some internal tool (MIAB or Linux) I can use to check the validation works?
Would relying on MIAB’s DNS fix this issue? ( I don’t want to do it but if I have no alternative I will )
I’ve tried using custom key values for the private and public keys on the DKIM config and in the DNS record my modifying DKIM’s KeyTable but somehow it got reset.
IN MX 50 mail.srv.herc.tech.
herc.me. IN TXT “v=spf1 mx -all”
_dmarc.herc.me. IN TXT “v=DMARC1; p=quarantine;”
mail._domainkey.herc.me. IN TXT (
“v=DKIM1; h=sha256; k=rsa; s=mail; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8A”
Any help would be great, thank you!