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.
EnglishDNS resolving issue on Cloudflare
- Edited
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. 
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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.
piperino So what can I do about that?
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
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classycraft3r
ask for removal from the RBL.
As well, google is your friend.
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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).
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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.
classycraft3r
PTR Records are only added in the in-addr.arpa. zones of the IP owner. But the A and PTR records should match.
Means you can put whatever PTR you want in cloudflare DNS, since they don’t own the IP Block it has no affect.
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