How to Change your mail port (Some ISP Block 25, 26 port)

Hello Friends
Some ISP s is blocked 25 and 26 port ( i am from Turkiye, Blocked port 25)
solve this issue:
1-  you change your master.cf     path: /etc/postfix/master.cf

# ==========================================================================
smtp      inet  n       -       n       -       -       smtpd
#  -o content_filter=smtp-amavis:127.0.0.1:10024
#  -o receive_override_options=no_address_mappings

TO :

# ==========================================================================
smtp      inet  n       -       n       -       -       smtpd
587     inet  n       -       n       -       -       smtpd
26      inet  n       -       n       -       -       smtpd
#  -o content_filter=smtp-amavis:127.0.0.1:10024
#  -o receive_override_options=no_address_mappings

2- add this 587  and 26 ports in  your firewall incoming and outgoing ports
Your CWP panel --->> Security --> CSF Firewall
                                                 after click First Blue button Firewall Configuration
             find ports line and add your ports. if you use ipv6 add your ports there line too.

# Allow incoming TCP ports
TCP_IN = "20,21,2222,25,26,53,80,110,143,443,465,587,993,995,2030,2031,10011,30033"

# Allow outgoing TCP ports
TCP_OUT = "20,21,2222,25,26,53,80,110,113,443,2030,2031,587,993,995,10011,30033"

Note: i am not sure for add both in and out lines, but i use both

and finally you restart your services or restart your server
good luck

Thank you for share

You can also use iptables or CSF for simply redirect the inbound/outbound connections to that ports to the one you need.  Without touch the config files but the CSF ports obviously. This is the perfect example for you (http://www.cyberciti.biz/faq/linux-port-redirection-with-iptables/)

About the inbound and outbound decision, you must add both.

Even if you think the port 25 for SMTP is a sending port, is not.
If you wanna send a email from that SMTP server, you must connect to the port 25 then pass the HELO commands and so on... so,

All the ports are usually inbound/outbound even if the service looks like just 1 way.

About smtp(25)/pop3(110) ports, one is the email, the other is the service for the users/accounts. Both of them uses inbound/outbound data.

You login to the pop3 to receive emails, and you connect to same machine at port 25 to connect the smtp port then send them.

Always there are a negotiation, so you must allow both directions.

Hello Friends
Some ISP s is blocked 25 and 26 port ( i am from Turkiye, Blocked port 25)
solve this issue:
1-  you change your master.cf     path: /etc/postfix/master.cf

# ==========================================================================
smtp      inet  n       -       n       -       -       smtpd
#  -o content_filter=smtp-amavis:127.0.0.1:10024
#  -o receive_override_options=no_address_mappings

TO :

# ==========================================================================
smtp      inet  n       -       n       -       -       smtpd
587     inet  n       -       n       -       -       smtpd
26      inet  n       -       n       -       -       smtpd
#  -o content_filter=smtp-amavis:127.0.0.1:10024
#  -o receive_override_options=no_address_mappings

2- add this 587  and 26 ports in  your firewall incoming and outgoing ports
Your CWP panel --->> Security --> CSF Firewall
                                                 after click First Blue button Firewall Configuration
             find ports line and add your ports. if you use ipv6 add your ports there line too.

# Allow incoming TCP ports
TCP_IN = "20,21,2222,25,26,53,80,110,143,443,465,587,993,995,2030,2031,10011,30033"

# Allow outgoing TCP ports
TCP_OUT = "20,21,2222,25,26,53,80,110,113,443,2030,2031,587,993,995,10011,30033"

Note: i am not sure for add both in and out lines, but i use both

and finally you restart your services or restart your server
good luck

Will it work for Google Cloud?

it doesn't work. mail still tries to go out using port 25. anyone has this working ? I dont want to use gmail as relay.

Hello Friends
Some ISP s is blocked 25 and 26 port ( i am from Turkiye, Blocked port 25)
solve this issue:
1-  you change your master.cf     path: /etc/postfix/master.cf

# ==========================================================================
smtp      inet  n       -       n       -       -       smtpd
#  -o content_filter=smtp-amavis:127.0.0.1:10024
#  -o receive_override_options=no_address_mappings

TO :

# ==========================================================================
smtp      inet  n       -       n       -       -       smtpd
587     inet  n       -       n       -       -       smtpd
26      inet  n       -       n       -       -       smtpd
#  -o content_filter=smtp-amavis:127.0.0.1:10024
#  -o receive_override_options=no_address_mappings

2- add this 587  and 26 ports in  your firewall incoming and outgoing ports
Your CWP panel --->> Security --> CSF Firewall
                                                 after click First Blue button Firewall Configuration
             find ports line and add your ports. if you use ipv6 add your ports there line too.

# Allow incoming TCP ports
TCP_IN = "20,21,2222,25,26,53,80,110,143,443,465,587,993,995,2030,2031,10011,30033"

# Allow outgoing TCP ports
TCP_OUT = "20,21,2222,25,26,53,80,110,113,443,2030,2031,587,993,995,10011,30033"

Note: i am not sure for add both in and out lines, but i use both

and finally you restart your services or restart your server
good luck

it doesn't work for me too. anyone find the solution?