Well it would take something pretty big to knock out the entire internet and actually keep it mostly down for any length of time. It is a distributed system covering a very wide area physically on the earth. So two 'ideas' that might knockout the internet.

1: A major virus/worm that infiltrates the back bone and all machines it is capable. This virus would have to disrupt communications, be hard stop and just clog the internet like a clogged toilet. Only it keeps coming back.

2: Something like a solar flare or magnetic storm that totally wipes out a large % of the communications backbone, along with the vast majority of electronic devices.

I mention these because of how hard it would be to seriously knock the vast majority of the internet for any length of time. Don't forget that all communication systems are very closely integrated. Data and phone use much of the same network.

In either case if this happened even today, it would almost be an apocalypse, at least for most 1st world countries because EVERYTHING is on computers, in databases and would be lost and/or not available. Who owns what? Who owes what? Where are my products? How much money do I have in the bank? It would be very difficult, most executives do business and make decisions based on computer programs, at the very least giving them market and production data.

My job requires the internet. I'd be out of a job. Even many manufacturing jobs are ultimately dependent on the internet or at the very least computers getting/sending data somewhere.

At first it would be a mild inconvenience, for about the first 5 minutes. After that, business communications would start to back up and the most hot issues would be done over the phone, though no one would think they need to Fedex 'thumb drives' with data around yet.

After an hour broadcast TV 'might' be the only major form of communication left. Without the network, even many/most satellites will become mostly useless. Things will be slowing down as work backs up since communications have broken down. After 10 hours cities will start to panic. After a day most large cities will be shut down, people will stay close to home, and most of the small community grocery stores will have a run on all stock as people buy to hoard away their food. After 5 days riots might start, many who have friends and family in a rural setting might have left to 'visit' them.

After two weeks if a coordinated effort can't be done because of lack of communication people are going to start going hungry.

After a month North and South Dakota will be wondering what they are going to do with this years harvest, since no one knows what the current market value is which means they don't know what to sell it for nor who's going to buy it. They might also notice that there have been a lot few people visiting Mount Rushmore and the badlands this year.

Well it would take something pretty big to knock out the entire internet and actually keep it mostly down for any length of time. It is a distributed system covering a very wide area physically on the earth. So two 'ideas' that might knockout the internet.

1: A major virus/worm that infiltrates the back bone and all machines it is capable. This virus would have to disrupt communications, be hard stop and just clog the internet like a clogged toilet. Only it keeps coming back.

2: Something like a solar flare or magnetic storm that totally wipes out a large % of the communications backbone, along with the vast majority of electronic devices.

I mention these because of how hard it would be to seriously knock the vast majority of the internet for any length of time. Don't forget that all communication systems are very closely integrated. Data and phone use much of the same network.

In either case if this happened even today, it would almost be an apocalypse, at least for most 1st world countries because EVERYTHING is on computers, in databases and would be lost and/or not available. Who owns what? Who owes what? Where are my products? How much money do I have in the bank? It would be very difficult, most executives do business and make decisions based on computer programs, at the very least giving them market and production data.

My job requires the internet. I'd be out of a job. Even many manufacturing jobs are ultimately dependent on the internet or at the very least computers getting/sending data somewhere.

At first it would be a mild inconvenience, for about the first 5 minutes. After that, business communications would start to back up and the most hot issues would be done over the phone, though no one would think they need to Fedex 'thumb drives' with data around yet.

After an hour broadcast TV 'might' be the only major form of communication left. Without the network, even many/most satellites will become mostly useless. Things will be slowing down as work backs up since communications have broken down. After 10 hours cities will start to panic. After a day most large cities will be shut down, people will stay close to home, and most of the small community grocery stores will have a run on all stock as people buy to hoard away their food. After 5 days riots might start, many who have friends and family in a rural setting might have left to 'visit' them.

(Burki's comment) Many hospitals and pharmacies are going to have issues too. Prescriptions will need to be written on paper again, but keep track of stock will be difficult. Hospitals need to interact with pharmacies, insurance companies and other health related places. Often even their own electronic records are offsite are accessed over the internet.

After two weeks if a coordinated effort can't be done because of lack of communication people are going to start going hungry.

After a month North and South Dakota will be wondering what they are going to do with this years harvest, since no one knows what the current market value is which means they don't know what to sell it for nor who's going to buy it. They might also notice that there have been a lot few people visiting Mount Rushmore and the badlands this year.