[TriLUG] marginally OT: Some bandwidth and DoS questions
Shawn William Taylor
STaylor at torexretailna.com
Tue May 29 13:29:24 EDT 2007
Responses in-line! I love this stuff.
-For a DSL connection with 768 down and 384 up, if you are consuming all
of the upstream bandwidth, does that mean you have no available
No, this is the point of asynchronous configuration. However, if your host
can not send things like acks to other communicating nodes then
effectively, the communication is lost or times out. (Hence the 'denial of
-For a T-1 with a nominal speed of 1.5 Mbps, is 1.5 the total available
bandwidth for upstream and downstream, with the entire pipe
theoretically available for unidirectional traffic (i.e. 1.5 Mbps down,
0 Mbps up)?
Most T1's are bidirectional. Again, it's less about consuming the pipe and
more about consuming the host.
-Have you ever heard of anyone (ab)using wget to accomplish a deliberate
non-distributed DoS attack?
-How much traffic/how many requests per second would be required to
effectively DoS a 768/384 DSL connection?
You would need a bunch of things all trying to talk at once. (I really
don't even have a guess but it would be a lot)
Even then it doesn't really need to consume the pipe, just overload the
-Could this be done with wget?
-Is there any resource on the internet which outlines how much data a
computer with a given processor is capable of putting on a network
Check out the manufacturers specs. Remember, each OS will have different
Default settings (obviously if it's a setting, it can be changed) so
things like network time-outs and such on the host are important in how
much data it can put through. As well if it's connection is Full-Duplex or
Half-Duplex will make a difference as well.
-Have you ever heard of anyone using wget to back up entire websites?
I hadn't heard of wGet before your email, however it looks like it would
do that quite nicely from the documentation. It seems that what it is
designed to do??
-Would using this method on a PHP-based website actually accomplish a
backup? It seems to me that it would only gather the generated HTML and
It seems to support wildcard file types so you could have your own
extension and it would pull it back.
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