The Monday 2005-01-24 at 15:29 +1100, Michael James wrote:
Best technical solution to the many-ISP situation is to have an authenticated SMTP host somewhere on the internet and always use it.
True. It also has to be reliable. You know, one of the reasons I started using my own sendmail was to get information (receipts) for sent mail from the server. Postifix doesn't honor them, but I can look at the log and know what happened. When I use an external relay, I don't know. The server can keep retrying for five days... sometimes, the email got lost and I never knew till I contacted the recipient some other way.
So the SMTP host effectively says, "Set up an encrypted channel, and prove that you're you, then I'll let you relay from anywhere."
Gmail provide this (and are pretty reliably available).
People seem to be very interested in gmail. I confess I haven't even bothered to look.
Always sending through the same SMTP relay becomes necessary to enable SPF records.
It needs having a domain name and reverse lookup, I suppose, so dial-up is ruled out. Even getting reverse lookup working is not easy: I know people here on fixed adsl and domain names (.org usually) with no reverse resolving, because the IP belongs to the provider, and they deny that service. Or so I understand.
SPF are DNS records that specify which SMTP hosts are allowed to send mail for your domain. (reverse MX records) SPF fixes all those virii flooding the internet with yours and my email picked out of some outlook address book and filled in as the sender. SPF lets a mailhost say, "Not sent from an authorised host, DROP it".
Have a look at: http://spf.pobox.com/
I'll have a look, I'm curious. -- Cheers, Carlos Robinson