Hey.
I heard about MailCow and wanted a mailserver to self-host on my VPS.
The issue I’ve came accross is that I cannot find a way to properly setup my DNS records.
I made all the records needed, verified them but the DNS check on MailCow UI prints out things that are different than what I putted on Cloudflare.
I don’t proxy any of the mail-related records, as I’ve seen that it causes issues (on this forum and other forums when I was searching for a solution).
Here are screenshots for y’all to see what the UI says, and what I’ve configured.
1 (UI): TEXT/HTML; CHARSET=UTF-8 1010x845 14 kBsafe.classydev.fr
2 (Cloudflare): TEXT/HTML; CHARSET=UTF-8 1153x80 14 kBsafe.classydev.fr
3 (Cloudflare): TEXT/HTML; CHARSET=UTF-8 1141x433 14 kBsafe.classydev.fr

And I cannot send or recieve any emails, even though all ports and open and accessible as I’ve tested.

Any ideas?

you should be able to receive mails if you have a mailbox created.
one problem is your PTR record. you should be able to change that in the Admin panel of your hoster.

it this might be your second problem.

And you’re sure you’re on a proper VPS and not behind a router from your internet provider with a DHCP address?

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    piperino What do you mean panel of hoster? I don’t have access to such a thing, I only have terminal access (the server is a server that is running in my friend’s network).
    The thing is that the PTR record is not supposed to be what mailcow detects (On cloudflare, as you can see on the screenshots, I’ve configured the mail.project-hestia.me to the IP (and not the weird domain) and the PTR record to mail.project-hestia.me so everything should work).
    And why is my friend’s IP blacklisted?
    As the server is at his home, it’s behind a router (Freebox) and I’ve configured the port redirection to allow all Mailcow ports and domains.

    EDIT: I saw that “82-65-80-184.subs.proxad.net” is a domain name associated with my friend’s router as proxad.net redirects to his internet provider’s website. But IDK why only for this record it shows the internet provider weird domain instead of the IP. (Also I saw that I am able to recieve emails through Mailcow but not send them as expected)

        classycraft3r
        If you would have rent VPS, you could adjust needed DNS setting for running a mailserver.
        Running a mailserver is quite different than running a simple webserver.
        Your friends IP is blacklisted because he has a DHCP IP assigned on his Modem.
        Long story short, you cannot run a mailserver behind ISP Modem/Router. period.
        Even mail is using SMTP (Simple Mail Transfer Protocol ) it’s not so simple.

            piperino So I should give up? There ain’t no way to run it? Everything works fine except for the sending of emails.
            (Also, he has a fixed IP because his dad has his servers in his home too, as he owns a society and needs to make backups to his servers)

                classycraft3r
                i don’t want to disappoint you. but yes. don’t try to run a mailserver behind an ISP modem.
                Look around for a cloud server with a static IP and start over if you’re really interested in to have your own mailer.
                but believe me, if you’re new to this topic it’s a steep learning curve to get this properly done. 🙂

                    piperino I don’t want to seem like a pushover, I also own a VPS with a fixed IP, but this is a complicated situation:
                    My VPS is a VM on another VPS as my american boss gives me a VPS on his. If my memory’s good he told me not to setup one, can’t remember why.
                    So I can’t really setup one on it.

                    Can I have the reasons why i can’t run the mailserver behind an ISP modem? (curiosity, I don’t wanna be annoying) Cause that’s my almost only option, and best as we will soon buy a good server (64Gb ram, 6 CPU Cores, 1To storage NVMe) that’ll be our primary server and will be on the home network, behind the ISP modem.

                        classycraft3r
                        you should not do it because of the problem you currently facing.
                        most prominent is the blacklisting. the majority of the well maintained mailservers out there are using RBL’s and your would never be able to properly sending mails.
                        The second reason is that your IP on the modem will change sooner or later. yes, you can go through the hassle and setup something like DynDNS or similar. but…..
                        Better save your money and rent a VPS for 10euros instead of buying hardware and messing around behind an ISP Modem.

                            piperino I see.
                            Also, the issue on my VPS, is that the host itself, the datacenter has the port 25 blocked and I (or my american boss) does not have a valid reason to have it open for a mailserver instead of getting a google workspace..

                              And if I have a fixed IP (which is the case, the operator allows advanced users to request one as they host servers on their network, which is our case), wouldn’t it be possible?

                                classycraft3r
                                A static ip is of course a step in the right direction. Just make sure it’s not listed on any RBL’s.
                                And also sort out the PTR.

                                    Why was the IP already blocked even though it had never been used in your service or for spam bots?

                                      piperino What do you mean by “sort out the PTR” ?
                                      As for the RBL’s we are blocked on 3 of them, we don’t know why as we never performed any spam or mail service before.

                                          Hestia
                                          don’t know. maybe it was abused by the previous owner.
                                          there is also a chance the whole subnet is blocked.

                                              classycraft3r
                                              ideal PTR should point to you mailserver.
                                              But at this point just start us google. there might be a basic guide installing and operate a mailserver😉

                                                  is there a way to unlock it?

                                                  It would be stupid if we suffered from it when we are not the cause of this problem

                                                  piperino As you can see on the screenshots, it should be pointing to it.

                                                  184.80.65.82.in-addr.arpa.project-hestia.me -> mail.project-hestia.me -> Mailserver IP
                                                  And mailcow resolves it as 82-65-80-184.subs.proxad.net

                                                  Also requests to gmail (outgoing emails) can’t seem to go through the Modem for some reason.
                                                  sudo traceroute -n -T -p 25 gmail-smtp-in.l.google.com gives me this:

                                                  traceroute to gmail-smtp-in.l.google.com (64.233.167.26), 30 hops max, 60 byte packets
 1  192.168.0.254  1.797 ms  2.515 ms  3.312 ms
 2  * * *
 3  * * *
 4  * * *
 5  * * *
 6  * * *
...

                                                  Also requests to gmail (outgoing emails) can’t seem to go through the Modem for some reason.
                                                  sudo traceroute -n -T -p 25 gmail-smtp-in.l.google.com gives me this:

                                                  traceroute to gmail-smtp-in.l.google.com (64.233.167.26), 30 hops max, 60 byte packets
 1  192.168.0.254  1.797 ms  2.515 ms  3.312 ms
 2  * * *
 3  * * *
 4  * * *
 5  * * *
 6  * * *
...

                                                  (sorry for the doubling, something went wrong on my side and it edited it two times).

                                                      classycraft3r I fixed the firewall issue, but now it sends emails, but I never recieve them. They appears and disappears from the queue and I still don’t get them.

                                                      EDIT: This is because of the PTR record. Now I really need to fix this.
                                                      EDIT 2: The weird this about the PTR record happens because the reverse DNS bring out the domain associated with our address. I’ll find a way to change this on their forum.

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