Re: [exim4] mixed up about terminology
On 10/5/2014 11:31 PM, Chris Bannister wrote:
> On Sun, Oct 05, 2014 at 11:16:18PM -0400, Harry Putnam wrote:
>> Jerry Stuckle <jstuckle@attglobal.net> writes:
>>
>>> The first question - why do you think you need to relay to other
>>> networks, even if they're your own? Do you have other SMTP servers
>>> running on those networks?
>>
>> Good question and apparently thee is no reason. It stemmed from a deep
>> seated confusion about what relaying means. All I really want is to
>> be able to do this:
>>
>> On my lan machines:
>>
>> HOST-1
>> HOST-2
>> [...]
>> HOST-mail-server now being configured
>>
>> HOST-[12...N] would have the server host above listed as smarthost in
>> there respective mail config.
>>
>> So they would all be sending mail by way of server host.
>>
>> I guess that is not what is meant by relaying?
>
> Good point. Just to be pedantic all MTAs act as relays, but I think the
> term being talked about is "open relay" IOW it's "open" for anybody to
> use, spammers, guy next door etc. etc.
>
One correction - all MTAs *CAN* act as relays. But sending a message
from the sender's MTA to the recipient's MTA is generally not considered
"relaying". A relay would be when there is a third (or fourth or
fifth...) MTA between the sender's and recipient's.
Only under special conditions would a relay be required. The most
obvious one I can think of is a large company with multiple sites; all
mail would go to ???@example.com, which would be one MTA. But this MTA
would then relay messages to MTAs at local sites around the world. And
the reverse would happen for messages being sent by employees.
Jerry
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