I was testing from LAN … I just tested online and the connection is denied. So, I should contact my ISP or is it my registrar I should contact?
Why are they blocking this service? 
Anyway, is port 25 required or can we just set the mail server up so that it runs on port 587 and SMTPS by default?
It sounds tricky though, because I know for instance that HTTPS (443) won’t work if you disable HTTP (80) … so … my hopes aren’t too high right now.
Anyway, here is the output of postconf -n … and I think I have redacted all sensitive information, please tell me if I have not.
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
allow_percent_hack = no
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = all
mail_owner = postfix
mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME
mailbox_size_limit = 0
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost, server1.XXXXX.tlp
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.10.1/README_FILES
sample_directory = /usr/share/doc/postfix-2.10.1/samples
sender_bcc_maps = hash:/etc/postfix/bcc
sender_dependent_default_transport_maps = hash:/etc/postfix/dependent
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_tls_security_level = may
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
unknown_local_recipient_reject_code = 550
virtual_alias_maps = hash:/etc/postfix/virtual
this is what I see at FirewallD
This are the outputs of iptables -nvL INPUT --line and OUTPUT
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 5687 1709K ACCEPT all – * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
2 187 12937 ACCEPT all – lo * 0.0.0.0/0 0.0.0.0/0
3 127 19942 INPUT_direct all – * * 0.0.0.0/0 0.0.0.0/0
4 119 19462 INPUT_ZONES_SOURCE all – * * 0.0.0.0/0 0.0.0.0/0
5 119 19462 INPUT_ZONES all – * * 0.0.0.0/0 0.0.0.0/0
6 0 0 DROP all – * * 0.0.0.0/0 0.0.0.0/0 ctstate INVALID
7 113 19118 REJECT all – * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibitedChain OUTPUT (policy ACCEPT 9565 packets, 821K bytes)
num pkts bytes target prot opt in out source destination
1 3625 746K ACCEPT all – * lo 0.0.0.0/0 0.0.0.0/0
2 9565 821K OUTPUT_direct all – * * 0.0.0.0/0 0.0.0.0/0
maybe it is not that ISP’s block port 25, but something else? And what do you mean by turn up? :turnip emoji not available:
I will have a look at the rest of your message during the weekend, I am too tired. But thanks for the help guys. I am learning a lot and some people might find this useful in the future 