"Dennis Ferguson" wrote in message
...
Frank Dresser wrote:
"Dennis Ferguson" wrote in message
...

Note that this is not a unique attribute, it is about the same
situation
as that which exists for broadband Internet service via cable modems.
I
assume that BPL would use the same protection techniques (mostly
depending on control of the receiving equipment, I think). This seems
to mostly work, I very seldom hear complaints about the security of
people's cable connections.

Yeah, I'm almost totally ignorant on this one. I sorta assumed the cable
companies set aside some bandwidth for internet access, and trapped it
out
for non-internet cable subscribers.

No, there's no traps for non-Internet cable subscribers. This is why
you can sometimes go to Best Buy, buy a cable modem, plug it in and
then call the cable company to program it on. Everything to everyone
in your neighbourhood is sent through one or more (unused for TV)
television channels, the cable modem gets it all, picks out those packets
which are addressed to you and discards the rest.

This is `secure' only because the configuration and operation of the
modems is controlled entirely by the operator on the RF side of the modem.
There is a standard called DOCSIS which the modems must conform to which
standardizes the configuration interface and is intended to minimize the
possibility that the user can fiddle with any of it. This seems to work
well enough (and maybe the idea of watching your neighbours' Internet
traffic is boring enough?) that I haven't heard of people hacking the
modems
the way they do digital cable and DBS receivers, though who knows?

In any case, I think whatever permits cable operators to sell their
service will work equally well for BPL since the situations are
exceedingly similar.

Dennis Ferguson


I know there is a trap in my house to keep the cable modem traffic from my
television equipment. I think this is basically to prevent the outgoing data
from interfering with the television equipment. (Outgoing = from me to the
world).

Also, every cable modem has a MAC address and the system's DHCP server would
not provide an IP address unless the MAC address is in the list allowed by
the DHCP server. In this way, normal users get their own data on the cable
modem party line. An unknown cable modem would have trouble connecting to
the net.

That's not to say that someone can't listen in on other's traffic with the
right equipment. Encryption is used to keep the data private.

Relative to BPL. There are traps already in place. BPL signals can't pass
through a transformer. In order to propagate BPL the power company will need
to add bypasses at each transformer.

Since BPL also requires repeaters approx. every 1/4 mile, there may not be
much interference beyond the immediate service areas.

Relative to " I very seldom hear complaints about the security of people's
cable connections". Cable is one big party line, if some on the local
section of the cable has sharing enabled, their system is visible. Everybody
has an IP address and all machines are addressable. If a machine is
lintening, and responds, you can make a connection to it. This why software
and hardware firewalls are important for cable modem users.

Just more fuel for the discussion.

Craig