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acumen 16th November 2009 06:50

smtp port other than 25
some of my client's port 25 blocked by their ISP. So, i want to add one more listen port to postfix. What's the best way?

1. can I change postfix conf file manually? master.conf? how? or,
2. I use ispconfig's firewall, can i also use iptables to redirect the additional port to 25?


damir 16th November 2009 10:14

Maybe you can find a answer here:

acumen 16th November 2009 18:57

ammm... what I want to do is, setup another port to redirect to port 25. Not the one smtps.

If I use ISPConfig's firewall, can I also setup the redirect just like iptables?


iptables -t nat -A PREROUTING -p tcp --dport 9925 -j REDIRECT --to-ports 25

radim_h 16th November 2009 19:31

All you have to do is go to /etc/postfix/ and uncomment
lines about submission and smtps.

Then you will be able use port:

25 - also with TLS Enctyption
465 - also with SSL Encryption
587 also with TLS Encryption

Don't forget allow these port in firewall if you use dome...

# Postfix master process configuration file. For details on the format
# of the file, see the master(5) manual page (command: "man 5 master").
# Do not forget to execute "postfix reload" after editing this file.
# ================================================== ========================
# service type private unpriv chroot wakeup maxproc command + args
# (yes) (yes) (yes) (never) (100)
# ================================================== ========================
smtp inet n - - - - smtpd
submission inet n - - - - smtpd
-o smtpd_tls_security_level=encrypt
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_sasl_authenticate d,reject
-o milter_macro_daemon_name=ORIGINATING
smtps inet n - - - - smtpd
-o smtpd_tls_wrappermode=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_sasl_authenticate d,reject
-o milter_macro_daemon_name=ORIGINATING

TheBirdMan 6th February 2010 02:12

SMTPs SSL/TLS secure?

I was wondering if someone could help me verify the security of smtps. I have configured Postfix (with ispconfig2) to use pop3s, Imaps and smtps port 645. The maillog shows they are all using TLS and thunderbird picks up the cert for ( When I use wireshark however smtps is using TCP not TLS. Is there something beyond my understanding going on? STARTTLS maybe?



falko 6th February 2010 20:46

TCP is just the protocol:
There's nothing wrong with that.

TheBirdMan 6th February 2010 22:37

Thank you,

Now I can sleep at night. :)

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