Mailing List CGatePro@mail.stalker.com Message #106564
From: Fred.Zwarts F.Zwarts@KVI.nl <CGatePro@mail.stalker.com>
Subject: Re: How to require authentication for SMTP
Date: Tue, 12 Sep 2017 09:40:43 +0200
To: <CGatePro@mail.stalker.com>
X-Mailer: Microsoft Windows Live Mail 16.4.3528.331
Thanks for the suggestion. In fact, I tried that already. With iptables it works fine for IPv4, but with ip6tables I did not succeed to make it working for IPv6.
So, it works in most cases, but I wondered why CGP does not offer a better solution.

So, I would like to add a feature request for this option. Clearly, there is a need for it, which can be honored currently only by external software meant for something else, such as VPN and firewall software.


Another way would be to open another port on your firewall, but redirect to CGP's 587.

Nicolas Hatier, ing. <nicolas.hatier@niversoft.com>
Niversoft idées logicielles - http://www.niversoft.com



On 2017-09-06 10:59, Mark J Strawcutter mjstraw@iup.edu wrote:
For those instances where 587 is blocked, can you provide them with a VPN service so they can open 587 thru that?

Mark

On 9/6/2017 3:39 AM, Fred.Zwarts F.Zwarts@KVI.nl wrote:
WE have set up a system with two SMTP ports. One is port 25, used for receiving mails sent to our users. The other one is port 587, the submission port, which is used by our users to send mail elsewhere. Port 587 requires authentication, which makes sure that only valid users send mail elsewhere. This port 587 is also used by our users when the are traveling, and when they are on networks of other providers.
Now it turns out that some providers block port 587. I don't understan why, but that does not matter, it is a fact and we cannot change it.
So, I want to offer my users another port, with the same properties as port 587. However, I cannot find a way to require authentication. It seems that port 587 is configured automagically to require authentication.
Does someone know how this can be accomplished? If not, is it a good idea for a new feature.

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