HOWTO: using alternative port for SMTP and PLESK

[NightMan]

Your customer may complain sometime they cannot use their SMTP server to sending mails out. Most probably the ISP started blocking 3rd party smtp servers.
In this case you can provide an alternative port for your customers to send mails out.
Or
Some customers having problem accessing your PLESK control panel using from their work but it working fine from their home. This is a case network admin at work is blocking the port 8443.

Here is a simple solution.
You can use your firwall to route all traffic coming to one port to another, no need to change or configure anything in the PLESK. no need to configure things again and again after every PLESK upgrade.

Just preroute the ports.

e.g: routing smtp port 25 to 3525
iptables -t nat -I PREROUTING -p tcp --dport 3625 -j REDIRECT --to-port 25

e.g: routing PSA access port 8443 to 3636
iptables -t nat -I PREROUTING -p tcp --dport 3636 -j REDIRECT --to-port 8443

if you are using APF firewall then just add following line to the preroute.rules file.
$IPT -t nat -I PREROUTING -p tcp --dport 3625 -j REDIRECT --to-port 25
$IPT -t nat -I PREROUTING -p tcp --dport 3636 -j REDIRECT --to-port 8443


Use it, test it. And I should not be held responsible for any misconfiguration of your firewall settings.

 

[atomicturtle]

Or just use port 465

 

[NightMan]

Originally posted by atomicturtle
Or just use port 465

that will prompt for a ssl certificate error(if you dont have installed a vaild one.) am I right?

 

[nerbonne]

That worked great. Thanks.

 

[nerbonne]

Just one question:

Will that command make the iptables rule permanent, or do I need to do something else?

I remember on my old box when I would block IP's with iptables, that the rules would be gone when I rebooted.

Please let me know. Thanks!

 

[NightMan]

you have to load your iptable rules after the reboot.

To autostart apf on reboot, run this:

chkconfig --level 2345 apf on

To remove it from autostart, run this:

chkconfig --del apf

some usefull information here.
http://gentoo-wiki.com/HOWTO_Iptables_for_newbies

 

[madsere]

Why make it so complicated? What's wrong with using this method:

http://kb.swsoft.com/article_22_837_en.html

 

[NightMan]

Originally posted by madsere
Why make it so complicated? What's wrong with using this method:

http://kb.swsoft.com/article_22_837_en.html

nothing wrong with this method. but when you upgrade the PLESK, then you have to make the changes again.

firewall method is simple and not affected by the PLESK upgrade. the same way you can give access to the PSA by another port than 8443.