Re: against a DDoS
People could block certain recipients quite easily. Especially when the gaps in the analog system became better known. There were tricks to get resources that you didn't pay for, often by finding someone else's resource unprotected. You could then use that to tie up one of the victim's lines. If you could get enough independent connections to close all of theirs, you could lock them out. Eventually, they would terminate your connections and you could race to reconnect before someone else did.
As for taking down the whole network, that wasn't as common. You couldn't call through all the lines available because they had different capacity in every area. Something to cut through wires would be more effective for a single area.
Biting the hand that feeds IT
