@Mizar
I have what sounds like a similar or maybe the same problem. But note that I am on dial-up still and I thought that this problem was specific to my bad phone line conditions, etc.
Any individual program stops communicating after some time. To keep AWeb working, I leave a page open with small images on it (e.g. a page like this in a forum) and ask to reload a small image when the xfer stops. After a while, I need to start a xfer several times to keep things going.
I haven't tried on my A1200, but this happens with my Amithlon box running Genesis and is also happens on my OS4 box.
A "solution" that works for my OS4 box is to open a command line shell and type "ping http://www.google.com interval 5" (for example) for the whole time I'm online. Xfers then only stall for five seconds or so, not forever.
And yes, the same problem afflicts my Linux box. It really seems to be something caused by bad line conditions or something at my ISP.
I am still on dial-up too. That was what I fogot to mention! I don't think it's bad phone lines. Like I said, this never used to happen to me, it just started up all the sudden in '08 at the same time as my ISP was updating their stuff (to what other ISPs are using). And if it really was bad connectivity through the phone lines, your strategy of reloading small images or using continuous pings would not help because data would still not be able to get through, in any case. I recall getting info in the past that suggested it is being caused by the prevalence of broadband, and therefore the dial-up accommodation is being compromised by the protocols that are so broadband oriented. So it is the second cause you mention- something at your ISP (and all ISPs anymore).
What do you mean by "any individual program" stops communicating after some time? Is it just AWeb (or other browsers) having transfer problems, or are you talking about other internet clients as well, ie. telnet, e-mail, etc.?
Most interesting that this transfer problem is occuring on Amithlon, OS4, and even Linux. The common factor here is the "dial-up" networking, I believe. Though this does not happen with Win browsers, even old ones. I had been using NetScape 4.74 on Win95 on dial-up also, and there were no transfer delay problems (just the usual dial-up slowness :-). Seems it's only quality OSs' browsers that are affected by the dial-up grinding-to-a-halt problem. :-(
My strategy of using telnet connections to keep AWeb's transfers going was rather a hassle. And it still is when repeatedly restarting AWeb or rebooting. I like your strategy better, especially of using continuous pings. I had thought of that and tried it some, but didn't keep it going for an extended time, so I didn't realize it worked! (on an A1200)
BTW, I'm not planning on staying with dial-up much longer, as there's still PCMCIA ethernet cards available :-). And they're not too expensive either. This further adds to what I have been wondering about, if switching to broadband would cure these darn web transfer problems. It's sounding like it :-). And even if dial-up weren't forever more plagued with such problems, broadband would still be so much faster and nicer.