The bot likely doesn't notice it lost connection.
The "status" of tcp connections only update when data is sent or received, because of this it usually just remains in "waiting for data" mode without noting there won't be any data cause the connection is gone.
this could be fixed by adding a 'ping' to bebot that sends a ping packet through the connection every 60 seconds or so.

I take it, you have reduced the time before attempted reconnect option in bot.conf?

-jj-

No idea ;-p  I think it is seconds tho.

$reconnect_time = 1;             // Time to wait for auto reconnect after an error has accured.

My setting :-)

-jj-

Reconnect time only comes into play after the bot is actually disconnected.
In this case, the bot simply isn't disconnected yet.

Basically what happens is that your ISP is disconnecting you, PHP is unaware of this and thinks everything is fine and dandy until the point where the bot tries to send some data on it's own initiative (which currently never happens iirc) or the connection actually times out due to lack of activity. Although im not sure if this timeout occurs in PHP, Windows or your router/modem.

I guess one could do some sort of ping, but i'd be weary of adding say 1 ping a minute doing for example a char lookup on the bots name simply because these things add up quickly. When you get anywhere from 200-2000 bots (i have noooooooo idea how many BeBots are out there), these pings every minute quickly add up.

No need for a char lookup, there's an actual ping packet intended for this purpose.
You'll even get a pong back.

not that I know off.
It's a really small packet, just the header and no data.
I think about a minute is ok.

It's actually something BeBot devs should be doing and releasing