This is on my fresh Trixie installation.
I checked the router (running libreCMC), the rules for forwarding these two ports are exactly identical to the rule for port 993, just with different port numbers, and I have no problem to fetch email from port 993. The local IP is correct. I am using the same router like before, with the same port forwarding rules, I only changed the local IP for all the port forwarding rules.
Something perhaps unrelated: I have a failed Let’s encrypt diagnostic for acccess to the freedombox with the domain name, but I actually have no problem to access it with that name, so I don’t know why it is failed (I re-ran diagnostics, it is still failed). Everything else is working fine, with diagnostics all ok.
I don’t know whether this carries any useful information, but the journal includes this repeatedly:
Aug 13 10:13:38 debian postfix/smtpd[28973]: disconnect from unknown[77.90.185.6] ehlo=1 quit=1 commands=2
Aug 13 10:13:39 debian postfix/smtpd[28927]: disconnect from unknown[193.46.255.41] ehlo=1 quit=1 commands=2
Aug 13 10:13:46 debian postfix/smtpd[28925]: connect from unknown[80.94.95.229]
Aug 13 10:13:47 debian postfix/smtpd[28973]: connect from unknown[77.90.185.6]
Aug 13 10:13:48 debian postfix/smtpd[28925]: disconnect from unknown[80.94.95.229] ehlo=1 quit=1 commands=2
Aug 13 10:13:49 debian postfix/smtpd[28973]: disconnect from unknown[77.90.185.6] ehlo=1 quit=1 commands=2
Aug 13 10:13:50 debian postfix/smtpd[28927]: warning: hostname hostingmailto095.statics.servermail.org does not resolve to address 193.46.255.185: No address associated with hostname
Aug 13 10:13:50 debian postfix/smtpd[28927]: connect from unknown[193.46.255.185]
Aug 13 10:13:52 debian postfix/smtpd[28927]: disconnect from unknown[193.46.255.185] ehlo=1 quit=1 commands=2
Aug 13 10:13:58 debian postfix/smtpd[28925]: connect from unknown[80.94.95.229]
Aug 13 10:13:59 debian postfix/smtpd[28973]: connect from unknown[185.93.89.229]
Aug 13 10:13:59 debian postfix/smtpd[28973]: NOQUEUE: lost connection after EHLO from unknown[185.93.89.229]
Aug 13 10:13:59 debian postfix/smtpd[28973]: disconnect from unknown[185.93.89.229] ehlo=1 commands=1
Aug 13 10:14:00 debian postfix/smtpd[28925]: disconnect from unknown[80.94.95.229] ehlo=1 quit=1 commands=2
Aug 13 10:14:07 debian postfix/smtpd[28927]: connect from unknown[77.90.185.6]
Aug 13 10:14:09 debian postfix/smtpd[28973]: warning: hostname hostingmailto190.statics.servermail.org does not resolve to address 193.46.255.41: No address associated with hostname
Aug 13 10:14:09 debian postfix/smtpd[28973]: connect from unknown[193.46.255.41]
Aug 13 10:14:09 debian postfix/smtpd[28925]: connect from unknown[80.94.95.229]
Aug 13 10:14:09 debian postfix/smtpd[28927]: disconnect from unknown[77.90.185.6] ehlo=1 quit=1 commands=2
Aug 13 10:14:10 debian postfix/smtpd[28925]: disconnect from unknown[80.94.95.229] ehlo=1 quit=1 commands=2
Aug 13 10:14:11 debian postfix/smtpd[28973]: disconnect from unknown[193.46.255.41] ehlo=1 quit=1 commands=2
Aug 13 10:14:17 debian postfix/smtpd[28927]: connect from unknown[77.90.185.6]
Aug 13 10:14:19 debian postfix/smtpd[28927]: disconnect from unknown[77.90.185.6] ehlo=1 quit=1 commands=2
Aug 13 10:14:20 debian postfix/smtpd[28925]: connect from unknown[80.94.95.229]
Aug 13 10:14:22 debian postfix/smtpd[28925]: disconnect from unknown[80.94.95.229] ehlo=1 quit=1 commands=2
Aug 13 10:14:23 debian postfix/smtpd[28973]: warning: hostname hostingmailto095.statics.servermail.org does not resolve to address 193.46.255.185: No address associated with hostname