About 2 weeks ago, my Cogeco connection started becoming erratic. After several days of this a technician came by to adjust my signal levels. He suggested that if I saw the same symptoms again I should probably swap my cable modem for another one. It worked fine up until last night when it started happening again.

I went to the retail office and got a new cable modem. The one I’d been using had been 4 years old and they’d updated their model. I took this one home and plugged it in. Everything was great – except that I wasn’t receiving any email because incoming IP traffic on port 25 was being blocked. (As, apparently, were some other ports which I didn’t care about.)

It seems as if Cogeco (and Sympatico) have both implemented policies in the past year and a half, whereby residential accounts have various ports blocked for incoming traffic. It’s not clear why they’re doing this. If it’s to prevent spammers, they should be blocking outgoing port 25, not incoming. Alternatively, if it’s to prevent services from being run by home users, there’s no rationale behind not also blocking other ports – like 80, 443, and 23.

Ironically, this port filtering is based on the cable modem unit you have – so if my old unit hadn’t given up the ghost, I’d still be happily receiving port 25 traffic. (A good friend of mine thinks that this is all a consipiracy to get older customers to bring in their “broken” units and force anybody who gets a new unit, with port filtering, to upgrade to a business account.)

In any case, I had to “immediately” upgrade to a business account, which doesn’t block any ports. All of this for an extra $60/month. (I do, however, get some higher bandwidth and a static IP out of the “deal”, so all is not negative.)