Hello,
I am running a Debian 12 server hosted at OVH. It's a fresh VPS, and the
domain I'm using for that test is ivanroth.fr, with the subdomain
mail.ivanroth.fr as advised in the article.
DNS and rDNS seems fine, host and dig reply what they are supposed to.
On the server, I created an account with my first name (ivan) and I am
using [email protected] as the test mail address.
* I cannot send a mail to myself ([email protected]) using mutt from
the server
* I cannot send from the outside to that address
* I cannot send from that address using Thunderbird
When looking at systemctl status opensmtpd, I see some errors I don't
understand like :
debian opensmtpd smtp-out: No valid route for
[connector:[]->[relay:ivanroth.fr,smtp],0x0]
Your smtp server can't be reached by others.
$ nc -4 mail.ivanroth.fr 25
Closes immediately: Server isn't running or firewall answers with
REJECT. It could be a iptables firewall on your VPS as well as one from
OVH. (I don't know OVH but I do know that some VPS providers have a
extra firewall you need to configure separately.)
$ nc -6 mail.ivanroth.fr 25
Eventually times out: IPv6 not working or a firewall is configured to
just DROP incoming packages. (I can't even ping your IPv6 address, while
IPv4 works.)
From all the ports(25, 465, 587, 143, 993) I have tested only IPv4
IMAP(143) is reachable. (Which is consistent with you saying Thunderbird
reading works.)
$ nc -4 mail.ivanroth.fr 143
* OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE
LITERAL+ STARTTLS LOGINDISABLED] Dovecot (Debian) ready.
^C
I don't really know where to start digging. If someone could point me to
some direction, it would be nice.
I would first suggest to get IPv4 working and therefore temporarily
removing the AAAA record from mail.ivanroth.fr.
Than check what is blocking port 25. Is it your Debian firewall or your
VPS provider.
You than most likely want to unblock port 465 or 587 for mail submission
with Thunderbird.
If after that you still have problems post your entire smptd.conf please.
Last step. Fix IPv6.
