Re: [exim4] mixed up about terminology
On 10/8/2014 7:55 AM, Brian wrote:
> On Tue 07 Oct 2014 at 22:25:01 -0400, Jerry Stuckle wrote:
>
>> On 10/6/2014 7:10 PM, lee wrote:
>>> Jerry Stuckle <jstuckle@attglobal.net> writes:
>>>
>>>>> dc_relay_nets
>>>>> A list of machines for which we serve as smarthost.
>>>>>
>>>>> That looks ideal, doesn't it?
>>>>>
>>>>>
>>>>
>>>> Right. But he's not running multiple MTAs - he only has the one, as he
>>>> already indicated.
>>>
>>> Does it make a difference for this setting whether the MTA is smarthost
>>> for other MTAs or for MUAs?
>>>
>>> (I'm not using the automatic config other than to create a
>>> "non-configured" exim which does nothing but use another host as
>>> smarthost to deliver locally generated messages, so I don't know.)
>>
>> Yes, it does. By definition, a smarthost talks to for other MTAs. MUAs
>> are not MTAs.
>
> By definition an MTA will transport mail. It will do this for whatever
> talks nicely to it (telnet or netcat would do). Exim has no idea whether
> it is communicating with an MUA or an MTA and doesn't care. In fact, it
> will happily listen on ports 25 and 587 at the same time.
>
> Mail submitted on either of these ports can require authentication or be
> restricted to being allowed only from designated networks, such as a LAN.
> Neither of these mechanisms is known to lead to an inherent insecurity.
>
>
Yes, I know all of that, Brian. But you missed the entire meaning of
the word "smarthost" as it applies to MTAs.
And yes, there are many possible insecurities in an MTA configuration.
Does the term "open relay" mean anything?
Jerry
Reply to: