Re: [exim] Exim 5.x

On 19 May 2011, at 18:27, W B Hacker wrote:

> Ian Eiloart wrote:
>>
>> On 19 May 2011, at 13:35, W B Hacker wrote:
>>
>>>>
>>>> part allows integration with an IMAP server, a message is
>>>> submitted with a an IMAP url to allow forward without download,
>>>> etc.
>>>
>>> ??
>>>
>>> IF the content is already located at a URI, all that is needed is
>>> the URI. We all get such - mostly as advertising.
>>
>> No, the point is not to put a URI in a message, but to put it in the
>> SMTP conversation. The URI refers to some content to be found on an
>> IMAP server. The SMTP server fetches that content, and appends it to
>> the message. The point is to avoid having your mobile device upload a
>> large attachment that's already available on the server.
>>
>
> But that protects only the *senders* handheld from overload.
>
> The recipient - who may ALSO be device, time, b/w, or all of the above constrained, gets the whole shebang. Like it or not.

Yes, it does. But that's fine. At worst, it means the benefit is halved. But there are other factors that improve the situation:

1. The recipient will often have better bandwidth.
2. Mobile devices usually don't download attachments without asking first.
3. I'm not an expert in such matters, but I believe that mobile connections are assymetric: sending data uses more power than receiving. Therefore one has less bandwidth to send than to receive. And, more power means less battery life.

And, yes, there are other ways of reducing bandwidth. But none of them apply in the case that I've received an email that I need to forward to a third party - perhaps so that they can deal with it while I'm away from the office.
>
>> Well 8bitmime is implemented almost everywhere.
>
> That one 'has traction', yes. And we should see what still needs doing...
>
> Such as MTA being able to detect lack of ability at the far-end, and reformat, or perhaps wrap - the whole of an often massive message.

That is the plan, apparently.

> Preferably on the fly and in-session rather than back-off, remember, and retry - so as to convey it in a manner the other MTA CAN accept.
>
> No mean feat in some instances, but the available horsepower is far more likely today than yesteryear.

Yes, I don't think horsepower is a serious issue for anyone with fewer than a million subscribers. Given that most large sites are fine with 8bitmime, translation will only be required for a minority of messages.

--
Ian Eiloart
Postmaster, University of Sussex
+44 (0) 1273 87-3148