>Now that I think of it, QMQP won't give your users the instant gratification
>they're looking for (i.e. not having to wait for the entire message to be
>transferred over the phone line). Since with mini-qmail there's no local
queue,
>they're still going to have to wait until the message is queued at the remote
>end of the phone line before their MUA cuts them loose. If you want mail
queued
>locally, you're back to where you started.
>
>Perhaps, as someone suggested, UUCP is your best option.
Well, that wont help as it happens. First off, qmail is going to do multiple
deliveries to the local uucp queue, so you'll still end up sending the
contents of the mail twice.
Second off, uucp was originally designed largely to cope with the error
rates of modem connections at the time. It wasn't designed particularly to
minimize transfer times. After all, uucp itself has no compression, it either
relies on the higher layers as with compressed news batches or lower layers
as in (more recently) V.42bis. Furthermore, the original 'g' protocol uses a
3x64 sliding window protocol which is way too small for line speeds over
2400bps.
All I'm saying is that uucp per se wasn't specifically designed to be
efficient, it was designed to work in the face of high error rates. Even
modern versions of uucp (such as those with protocol 'i') are not going to
be significantly more efficient at transfers than, say, a PPP connection
over the same line.
This is not to say that you can't layer a compressed mail transfer over uucp
such as compressed BSMTP, but that doesn't help solve the first problem and
in all cases you need special code at the other end.
A simple-ish solution is to plonk all your outbound mail into a Maildir,
then whenever you establish your PPP link, run a script which tar/gzips the
outbound Maildir and send the gzipped file to the other end to be unpacked
and injected into their mail system.
There are any number of ways to transfer the gzipped file depending on the
capabilities allowed at the other end. You could ssh it, you could
uucp-over-tcp it, you could ftp it...
The key is that you get to gzip all of the pending mails together, which
gives quite good compression for nearly identical mails. This is vastly
superior to simply gzipping each individual mail.
Here's an example. The text of this mail was duplicated in a file 1, 2, 4
and 10 times. Each file was gzipped. Here are the numbers:
Original size: 2242
1 copy gzipped: 1145
2 copies gzipped: 1177
4 copies gzipped: 1221
10 copies gzipped: 1336
Regards.
