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I'm doing a little research on how you can run your own e-mail server for your domain. I know that you can use Zoho, or gmail, or any other alternative. However, I'm wondering if it's possible to do it on your own - especially for a non-busy domains. Disclaimer: I am not in an unsolicited e-mail business.

I'm using the VPS from my current hosting provider. I've set up iRedMail which is basically a collection of open source pieces to run the full system automatically.

I set SPF record (very strict), I configured dkim, I added dmarc. I've added domain to google postmaster tools. I've checked, that my IP address is not blacklisted for junk mail.

The only recommendation that I decided not to follow was setting up a reverse DNS record for my IP address. I know how to do it, my hosting provider allows to do it, but my ultimate goal is to run multiple domains on single server/iredmail installation. And my hosting provider doesn't let me use multiple IPs on single VPS. So, even if I change PTR so that my IP address matches my first domain name, it won't match all of the others.

Almost everything works. I can send the mail, I can receive the mail. However, gmail is blocking me for 421-4.7.28 UnsolicitedRateLimitError reasons, which is silly, because I sent like 5 emails in total and all of them 1) at different times 2) to myself only - to test how it works.

My question is: am I missing something in configuration and there's actually a way to get those e-mails delivered to gmail without 12-24 hour delays? Or reverse PTR is critical for e-mail health and gmail won't accept e-mails unless the originating IP address is matching the sender's domain?

I read gmail guidelines, and since I'm not sending any bulk e-mail (and not really planning), the only thing I haven't done is the PTR record.

P.S. I'm using ipv4 (if it matters).

Val Petruchek
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  • You really do need to set the PTR record. It doesn't matter if you send mail for multiple domains. – Michael Hampton Aug 10 '20 at 16:24
  • @MichaelHampton, any PTR record? If I want to host mail.business1.com and mail.business2.com, can I just set it to mailcenter.mystudio.com and this will be enough? My understanding is that IP should resolve to mail.businessX.com, am I wrong? – Val Petruchek Aug 10 '20 at 16:32
  • It should be in your domain and match both how the mail server software identifies itself, and also match the DNS A and AAAA records. Consider Google. They send mail for many domains, but all of their servers identify themselves as something.google.com and have matching PTR records. Your setup should be similar, even if you are much smaller than Google. – Michael Hampton Aug 10 '20 at 16:33
  • So, it doesn't have to be mail.business1.com? I failed to understand that part. As I said, I don't have a problem setting PTR record, my hosting provider does that automatically, my assumption was that I need PTR record to be from the same domain as the emails. Thank you SO MUCH. – Val Petruchek Aug 10 '20 at 16:41
  • It doesn't have to be from any of the domains that you send mail from. It just has to match the A/AAAA records, and what the mail server sends in the HELO/EHLO. Usually this is just the machine's hostname. – Michael Hampton Aug 10 '20 at 16:43

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It really is best to have the PTR record and SPF record for your domain. the MX records should also be tight where possible. Many big hosts will delay or block you as spam without correct domain settings. I use mxtoolbox.com to check my domains when setting up mail servers etc. If it passses on all checks there - then it will usually work ok.

Ozoid
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I'm doing a little research on how you can run your own e-mail server for your domain.

There is absolutely no research needed - you also do not research to find out whether you can order pizza online. Pretty much every non trivial company runs their own server, as does pretty much every ISP.

I'm wondering if it's possible to do it on your own - especially for a non-busy domains.

There is no such thing as a business or non business domain. A domain is a domain is a domain is a domain.

The only recommendation that I decided not to follow was setting up a reverse DNS record for my IP address.

Yeah. My car does not work. The ONLY recommendation I do not follow is filling up the gas tank. Any reason it does not work?

The reverse DNS record must match the name the DNS server publishes in the HELO answer. This is not optional, and not a recommendation. It is a core setup for SPAM - because basically you can not change the reverse DNS for end user assigned addresses and their coding tells you that they are a pool.

So, you do not do a basic setup part. And THEN wonder you get classified as Spam. Welcome to the real world where you basically make sure you do not look like a spammer.

TomTom
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