Email! A great example of a nearly ubiquitous tool that relatively few people appreciate how difficult it is to actually provide as a stable service. The volume of traffic can be quite enormous while the ratio of useful information to spam is (without spam filters in place) as little as 1:100. The task of delivery is somewhat unique for the type of service it provides, rather than submitting to a central authority for delivery (as is the case in ordinary mail and telephones) each email server has the option to deliver email directly to the recipient's address (or at least to the equivalent to a mail room).
It is exactly this "feature" that has been the scourge of the Internet, of course, allowing "spammers" to send their garbage very easily from virtually any computer connected to the Internet. When the vast majority of connections were done through modems, the problem was fairly easily contained but with the introduction of broadband it became simple to put an email server in a house and start spewing email. In reaction to this we find that large broadband providers, like Rogers here in Canada, filter access TO AND FROM port 25 connections ... that is, one is not allowed to host an email server (on port 25) and one is not allowed to connect to arbitrary servers on port 25.
Thus it was that GATE Village found itself...with the knowledge and confidence of how to run an email service but with an ISP that refused to allow it :-) We muddled through for months, relying on a low-cost, low-budget and (unfortunately as it turned out) low-skilled service that has worked well enough up until very recently. Now, as I said, I know a lot about running email services and the kind of failures that just started turning up are of the sort that it would take hours of tracking, talking with support, and probably getting managers involved to fix ... it is a policy/configuration issue and when you pay very little for a service you get very little input into a policy issue.
As we knew we'd be moving to a much better data centre in the New Year (and in fact the service is switched over to the new centre this coming weekend!), we'd be able to host our own email services and FIX this problem once and for all. But life is twisty at times, it seems that the boogeyman simply didn't want a completely smooth service cut-over...our current ISP has been bouncing our email all over the place, even though the volume of email is incredibly low (it isn't core to our business of course).
Thankfully for our customers, we've long since taken over DELIVERY of outgoing email, it was only incoming email that we left to the old ISP, so our customers haven't been as affected, except of course when they want to reach us (of course, the primary method at /contact is completely local and words flawlessly). But we still have this very embarrassing problem and so here I find myself once again building solid email servers knowing that I'll have to once again deal with spammers, junk email, and unpredictable resource use ... I truly thought I'd left those days behind, but my standards are high and they are not being met by our current provider so what is one to do? sigh