Denial of Service

[John E]

Does anyone know what a Denial of Service attack is? I've often heard the phrase but I don't know much about it.

The reason I'm asking is that for well over a week now, my ISP has been providing no connectivity whatsoever during normal office hours. Every morning, somewhere between 9:00am and 10:00am my broadband connection disappears - then bang on the dot of 18:00 it comes back again. My ISP is blaming server maintenance being carried out by my local telco (British Telecom). However, I spoke to British Telecom who deny all knowledge.

I reckon that either someone has carried out one of these DoS attacks on my ISP or maybe they haven't paid their bills and someone is cutting them off during business hours. Has anyone else ever suffered anything similar to this? :mad:

[khp]

Originally posted by John E
Does anyone know what a Denial of Service attack is? I've often heard the phrase but I don't know much about it.


DoS generally refers to attacks that hinders the opration of some service (most often a web site), by flooding the machine that runs the service with a large amount of bogus requests, which appears to be legitimate to the server, this forces the server to waste most of it's time on these bogus requests, which means that very few legitimate requests will get through.
DoS attacks most commonly attacks web servers, but have also been known to target DNS servers and Email servers.
Using a DoS attack to knock out your Internet connection, is an order of magnitude more difficult, since it would need to knockout a router, which is usually more than a little difficult.

Originally posted by John E
The reason I'm asking is that for well over a week now, my ISP has been providing no connectivity whatsoever during normal office hours. Every morning, somewhere between 9:00am and 10:00am my broadband connection disappears - then bang on the dot of 18:00 it comes back again. My ISP is blaming server maintenance being carried out by my local telco (British Telecom). However, I spoke to British Telecom who deny all knowledge.


Maintenance work seems like a much more plausible explanation. Sustaining a DoS attack for 8-9 hours, seems rather unlikely, and why would an attacker stick to a specific schedule.
You need to confront you ISP, with British Telecom's claim not to be doing any maintenance, and demand that they fix it immediaetly, call them every hour while the problem persists. Untill they can at the very least, tell you when the problem will be solved, or send out a technician to have a look at the problem.
There is absolutly no way you can do anything to fix this on your own, the problem has to be worked out between your ISP and BT.

[John E]

Originally posted by khp
Maintenance work seems like a much more plausible explanation. I'd be inclined to agree if it went down for a couple of hours but to be honest, British Telecom is a pretty responsible company. Although there's no 'convenient' time for this kind of maintenance, for such a huge amount, I think they'd probably do it at night or weekends - not in the day, when the vast majority are expecting the service to be up and running. I tried ringing my ISP about 10 times yesterday but it was obvious they'd just taken their phones "off the hook".

Thanks for the help. It'll be interesting to see what happens on Monday...!

[Joseph_R_Thomas]

so what happened?everything ok now?

[hometown]

I guess it is Okay , right ?

[John E]

It's still Sunday here at the moment so everything's still okay (it all seems to work fine while we're outside of office hours). Can't wait for tomorrow tho'....

[khp]

Does your ISP run a News(NNTP) server ?.

If so, they might have a news group for local user issues. You should be able to find it, by doing a search for group names, that contains the name of your ISP.

If other users are having simmilar problems, you will most likely find something about it in such a news group.

[John E]

Well, here's a turn up for the books! It's now early evening on Tuesday (UK time). During both Monday and Tuesday the service was off between 09:00 and 17:00 (instead of 10:00 to 18:00, like I had last week). Why is this significant? Because daylight saving time started in the UK last weekend. This means that it's going off for exactly the same period as last week - except that our clocks have changed. To me, this doesn't sound like someone doing maintenance work because why would they be working different hours this week compared to last week?

I don't know what it proves though - I'm still as mystified now as I was a week ago. Time to find a new ISP I think...! :mad:

[gjs368]

Originally posted by John E
daylight saving time started in the UK last weekend.So, I guess that not all the lemmings live in the U.S. after all... :p