From Newsgroup: comp.misc

I've got a FreeBSD running as a Lightsail instance at AWS. I asked AWS
to create a reverse dns for my host and also lift all restrictions on
port 25. They did so: the reverse dns has been created and I can get
mails from the outside, but I can't seem to go out on TCP port 25. That
still seems blocked at least as far as the hosts I've tried to reach.
This might not have anything to do with AWS. AWS said that "[e]mail
sending limitations have also been removed for any resources for the
region your EIP is located in." I believe them.

The host 69.164.210.174 can reach my host at mx.antartida.xyz just
fine. The host mx.antartida.xyz is also named a.antartida.xyz.

%telnet mx.antartida.xyz 25
Trying 34.197.192.71...
Connected to mx.antartida.xyz.
Escape character is '^]'.
220 a.antartida.xyz ESMTP Sendmail 8.17.1/8.17.1; Fri, 18 Oct 2024 10:24:01 -0300 (-03)
help
214-2.0.0 This is sendmail version 8.17.1
214-2.0.0 Topics:
214-2.0.0 HELO EHLO MAIL RCPT DATA
214-2.0.0 RSET NOOP QUIT HELP VRFY
214-2.0.0 EXPN VERB ETRN DSN AUTH
214-2.0.0 STARTTLS
214-2.0.0 For more info use "HELP <topic>".
214-2.0.0 To report bugs in the implementation see
214-2.0.0 http://www.sendmail.org/email-addresses.html
214-2.0.0 For local information send email to Postmaster at your site.
214 2.0.0 End of HELP info
quit
221 2.0.0 a.antartida.xyz