[Pkg-exim4-users] Exim4 with local network as well as smarthost (longish post)

[ael]

Jeroen van Aart wrote:
> ael wrote:
>> The standard debian exim configurations do not seem to cater
>> for a small local network behind a NAT router.
> 
> Actually it's not the job of an MTA to do this. I have an instance of 
> exim setup behind a NAT router and it works flawless (including 
> spamfiltering and what have you). Just make sure you route port 25 and 
> whatever else to the proper internal IP. Provided you don't sabotage 
> yourself...
> 
>> Most mail needs to go to an (isp) smarthost with FROM headers
>> rewritten. But local mail within the network needs to be delivered
>> directly with headers unchanged.
> 
>> This already presents a problem to exim4 because, as I understand it,
>> envelope rewriting can only be done globally.
> 
> I do not know of any rewriting of the headers that needs to be done to 
> send email within the network as well as to the outside. 

That's the point: I *don't* want any rewriting for mail within the local 
network, but it *must* be done for mail to the smarthost. If the 
envelope rewriting is global, then I can't satisfy both requirements. Or 
am I missing something?


> Beyond that 
> which the standard exim4-config configurations options may decide upon. 
> I believe the only thing that might cause a header rewrite is the "hide 
> machine" name option, but I am not sure.
> 
> In your case you might prefer to have the machine name not hidden.
> 
>> My local network is small and no single machine is necessarily
>> running at all times. Thus a dedicated local network mail machine
> 
> That's what I mean by sabotaging yourself, you really should have one 
> machine intended to run all the time as the mailserve

It is not hard, but it is a ridiculous waste of energy: this is a 
*small* domestic network. I did say explicitly above that this sort of 
solution was not appropriate here.

> That machine will be the gateway and is configured as an internet facing 
> mailserver, 

Yes, I understand that approach: I read the archives and searched 
elsewhere and saw that sort of solution before posting. For a small 
office or business, it would be very sensible. But a profligate waste of 
precious resources in a lightly used domestic system.

Surely Debian should cater for all sorts of users in as flexible a way 
as possible?

But thanks for the reply: you seem to be confirming my feeling that this 
is an inherent limitation of the current version of exim.

ael