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Re: t-dsl

Stefan Nobis wrote:
> Nathan E Norman <nnorman@canaris.midco.net> writes:
> > Smart people *can* get IPs that haven't been assigned to them, and
> > it's a PITA to root them out.  PPPoE, while a hack, addresses this
> > concern for providers.  I wish we used it.
> Tell me more about this. What about configuring the routers only to
> route IPs that are assigned on each connection? In the worst case you
> set for each connection a static IP. How can anyone use IPs they
> haven't been assigned to in this case?

 My dear friends, you are totally wrong. But you can learn :-)

 PPPoE is used, because that way the telco can make sure you must change
the IP-adress from time to time and therefore you are stopped from
"missusing" your "client-only-line" for "server-use", which would
question other products of the telco:

 german telekom eg. charges around 48 Euro for a flat adsl-rate
(768kbit/s down, 128 up) and you must use a dynamic ip-number.

 a comparable solution also by the german telekom is t-interconnect,
512kBit bidirectional sdsl with a fixed number and costing around 100
Euro for the line and 40 Euro per Gigabyte! You can get as many
IP-Numbers as you can explain in a ripe-141-template (dont ask :-).

 (Yes, this IS totaly, absolutly braindead, but its the truth - and
thats the reason why I get bored by the x-files, because after all the
big "truth out there" simply is "there are only idiots out there" :-)

 ah, yes, back to topic: actually chances are good that you can use a
nearly fixed ip. Last time I checked t-online, which uses the same
radius/ppp-system like t-adsl, you could NACK and SUGGEST IPs while
handshaking until you found a number fit for your purpose. Bad: If your
ip is already being used, you lost.

 I dont have t-adsl now, but as I have already worked with dsl at work I
know that t-online uses just some dozend lines per router and this
router has enough ips for all lines. So I bet a "fried pink cow on white
bread" that you can always reserve the last number of the pool. Ok, some
hacking in the pppd should do the trick...

> Do you want to tell me that for leased lines there is no way to stop
> bad people to use IPs that haven't been assigned to them? Where is the
> big difference between leased lines and DSL?

 Actually PPP makes it easier to missuse ip-adresses, because with
ppp-over-ethernet you can under some circumstances even allocate several
ips at once (which doesnt make much sense). If you give a customer a
fixed IP you need only to make sure, that his router-port uses an
algorithmus named back-route-verity - then only his official ip may pass.

> I'm a beginner in the networking section but even i know some ways to
> secure the ISP-side. I can't imagine that all those big ISP like
> Worldcom/UUnet have no idea how to secure their IPs.

 Actually those big guys do not have a clue about technology, but they
know to protect their financial assets...

Christian Brandt

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