This seems an issue mostly with server "suspiciousness", of which reputation is a component.

Of the factors effecting suspiciousness, only two are local to the smtp server:
1.  DKIM signatures
2.  TLS certificates

To address these, confirm that both are working properly:
1. DKIM: send an email to a "dkim reflector" and then examine the email you get back. This pages discusses:

2. Use a proper TLS certificate. By proper, I mean one that verifies. Therefore you need to either purchase one or use "Let's Encrypt". I've been using Lets Encrypt certs for the last year without any problems. Setting up the client is not difficult, and it subsequently auto-renews every 60 days.

The remaining factors are outside your server, but just as important:
1. Reverse-DNS yields same result as the domain MX record. This is known as FCRDNS (forward-confirmed reverse DNS). Additionally, that result must not resemble a dynamic IP address (i.e. have the IP address in the domain name).
2.  SPF is properly set up.
3.  DMARC set up and working properly.
4.  Age of the domain name.  If created recently, that looks bad.
5. Presence of IP on blacklists. That is not hard to check. If you acquired an IP recently, it's former owner may have earned it a place on a blacklist. Easiest fix for that seems to be to get a different IP.

I'm curious to hear what others might add to this.

A good place for ideas is to browse through the spamdyke.conf file and think about all of the things it checks. Gmail is certainly using similar data points, but with neural network analysis rather than simple pass/fail rules.

For those who have set up a second server to test things, there is a good chance something above is not set up or does not support the new server. Gone are the days when you can bring a new parallel server online and start sending mails immediately. There are lots of "i's" to dot and "t's" to cross before other servers will confidently accept your mail.

Another thought: will give you a report about an email ADDRESS's reputation. It is interesting. Here is the result for mine (I replaced my email address for posting):

    "email": "first.l...@example.tld",
    "reputation": "low",
    "suspicious": true,
    "references": 1,
    "details": {
        "blacklisted": false,
        "malicious_activity": false,
        "malicious_activity_recent": false,
        "credentials_leaked": false,
        "credentials_leaked_recent": false,
        "data_breach": false,
        "first_seen": "never",
        "last_seen": "never",
        "domain_exists": true,
        "domain_reputation": "low",
        "new_domain": false,
        "days_since_domain_creation": 5654,
        "suspicious_tld": false,
        "spam": false,
        "free_provider": false,
        "disposable": false,
        "deliverable": false,
        "accept_all": false,
        "valid_mx": true,
        "spoofable": false,
        "spf_strict": true,
        "dmarc_enforced": true,
        "profiles": []

Though my domain and address are over 10 years old and never been blacklisted, the address gets a "low" reputation. I'm quite sure that is because it has determined that my email address cannot accept emails. But it is incorrect. After testing it a few times, I'm fairly confident that it decides that mostly because it tries to connect to my server from, whose IP ( is blocked by Spamdyke due to being on some blacklist. Therefore it concludes that I'm "risky". Also, they feel the risk is increased because my email has never been seen on social media, in credential breaches, etc. But I feel it is a triumph that I've kept my email address off of places where spammers harvest addresses.

Gmail is almost certainly considering all these factor and many more in deciding whether an email is rejected, sent to spam folder, or sent to inbox. That said, my wife uses gmail and we send numerous emails back and forth daily without any problem.

It used to be that setting up an smtp server was the hard part of running your own server. But times have changed, and now factors external to your network seem far more complicated and consequential than the server itself.

Again, I'm curious to hear other people thoughts.


PS: regarding the question of multiple certs, I do not see how that could work on the toaster. And in general, smtp does not work that way. The cert merely needs to be for the domain name pointed to by the MX record of the destination domain. There is no requirement that the destination domain be the name on the server certificate. Thus numerous virtual domains all have MX records which point to the same server; that server's cert merely needs to be for its own domain name, not those of all its virtual domains. For incoming mail, when connecting to a server and upgrading an smtp connection to a STARTTLS session, I don't think that the STARTTLS command has a way to specify the destination address's domain. That would need to happen for a server to know which certificate to use. For outgoing mail, it is theoretically easy to do, but someone would need to write a qmail patch to implement it.

DKIM works differently: each virtual domain has it's own dkim signing key. The toaster supports that, but it must be done manually (i.e. it does not occur when creating domains with vqadmin). Adding that functionality into vqadmin might be a good project for someone.

I did not intend for this to be so long.  It just happened.

On 8/26/2019 11:05 PM, Remo Mattei wrote:
Ok guys.. needs some suggestions..
I found out that the client (apple Mail) does not honor the DKIM since gmail said failed. I tested with Outlook and web round cube and that does pass the email DKIM and the message does not go into the spam folder in fact.

Any help will be great.. I also wonder if there is a way to setup multiple certs for the SMTP (per domain).


On Aug 26, 2019, at 12:03, Tahnan Al Anas < <>> wrote:

Basically Gmail put mail in spam folder for various reasons, I have found after hosing new domain in my qmail server, I need to check spf, dkim dmarc settings, even if all are ok, still gmail sent mail to spam folder, I need to check reverse forward record and also need to work to improve domain reputation, this is not an issue with qmail server, rather it is related with gmail's filtering. You have to work to improve server and domain's reputation for that.

Sometime I chat with google to get my other domain's mail in inbox by sending them to gsuite account.


Best Regards
Muhammad Tahnan Al Anas

On Mon, Aug 26, 2019 at 11:01 PM Eric Broch < <>> wrote:

    Create a google (gmail) account if you don't have one. Send an
    email to that account from the postmaster of the problematic
    domain. Open message, go to three vertical dots to the upper right
    of the interface, find 'show original', there you will see why
    gmail spammed your message.

    On Mon, Aug 26, 2019 at 10:51 AM Remo Mattei <
    <>> wrote:

        I just tested and I built a new qmail box


        The other two boxes

        So when sending from the new env which does not have any load
        no production etc.. the gmail gets the message in the inbox
        from the other two I get the msg on the spam folder.. I
        wonder.. how is Google…. Check the messages.. The new box I
        have even a domain called
        <> which it’s bogus!! But still in the

        Any tips?


        On Aug 25, 2019, at 21:10, ChandranManikandan
        < <>> wrote:

        Hi Folks,

        Emails are delivering to the spam or junk folder when users
        send to the recipients.
        Mostly  it's all public domain like gmail,yahoo etc..
        How to fix this issue in our server.
        Am using Centos 6 32 bit with qmailtoaster.
        Could anyone help me.

-- */Regards,

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