[Mimedefang] filter_sender, authenticated or smtp (port 25) Connections

Philip Prindeville philipp_subx at redfish-solutions.com
Sat Mar 3 15:03:39 EST 2012

On 2/20/12 1:26 AM, Jobst Schmalenbach wrote:
> On Sat, Feb 18, 2012 at 04:17:58PM +0100, Tilman Schmidt (t.schmidt at phoenixsoftware.de) wrote:
>> Hash: SHA1
>> Am 18.02.2012 06:57, schrieb Jobst Schmalenbach:
>>> I have a mailserver that staff on mobile devices can use for sending email on behalf of our domain.
>>> This is done using port 465, ssl and authentication.
>> Is there any reason why you don't use the Mail Submission port 587 which
>> has been designated specifically for that purpose?
> Yes, a number of things.
> A number of clients (this includes thunderbird and some apple clients) come by default sset to 465 so I guess that is one reason why I chose this. The other point is that port 465 is an SSL channel with SMTP inside it, so right from the start on the data is encrypted.

I don't think 2 wrongs make a right, and in any case this problem has been fixed (finally!):


> [root ~] #>grep smtp /etc/services 
> smtp            25/tcp          mail
> smtp            25/udp          mail
> smtps           465/tcp                         # SMTP over SSL (TLS)
> But AFAIK both are correct.

Well, that's wrong. Going to IANA, I see:


    <description>URL Rendesvous Directory for SSM</description>

465 has *never* been allocated to SMTP.  Period.

It was hijacked.


> Jobst

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