Re: [Sheflug] igmp packets...... it's getting worse....

[Jim Jackson <nospam [at] comp.leeds.ac.uk>]

On Tue, 21 Nov 2000, Chris J/#6 wrote:

> 
> > 
> > Are you sure about bridges?  I thought the whole point of a bridge was
> > to make physically separate networks look like a single one.
> > 
> 
> Hmm...guess it depends on the bridge :) Yes bridges are meant to connect two 
> segments (or seperate two segments), but many, IIRC, are vaguely intelligent 
> and keep track of MAC's on each side of it so only traffic that needs to 
> cross the bridge goes over.

correct - and remember a switch is just a multiport bridge :-)
If the switch/bridge knows which port a MAC address is then Unicast packets
are only sent down that port. If it hasn't a clue it broadcasts the packet to
all ports. Broadcast packets go to all ports. Some switches are intelligent
with multicast packets and attempt to do intelligent things like only send
multicast groups down ports that it has seen join requests for etc. Simple
switches just broadcast multicast packets.

> 
> > Unfortunately, the cops do not; spying on you is a lot more
> > entertaining and profitable than trying to prevent pickpocketing in
> > Picadilly.  Watch those laws carefully.  Note that Frenchmen do not
> > have the right to use encryption, and the U.S. government's "Clipper"
> > initiatives.
> 
> Umm...the French do, at least if my memory serves right. Not so long ago the 
> restrictions on cryptography was removed totally from French law.
> 
> > 
> >     Chris> plus they have silly amounts of data going over them.
> > 
> > Echelon is technically and probably financially feasible.
> > 
> 
> ..and is being investigated rather heavily by the EU (last I heard in the 
> computing press). Lots of docs and links about Echelon at 
> http://cryptome.org/cryptout.htm#Echelon
> 
> > 
> > No.  Your paranoia is insufficient.  If you have sensitive
> > communications, you probably also have a _specific_ sensitive
> > correspondent (your bank, your lawyer, il capo di tutti capi,
> > President Putin, "Monica", ...) and they can be targeted, too.  In
> > fact, that's more likely than targeting you---due to their large
> > traffic, such institutions are likely to be _less_ secure than
> > you---and history indicates that they are less aware of the problem
> > than the average denizen of ShefLUG.
> 
> My paranoia is sufficient for me :)
> 
> It all comes down to how paranoid you are about having your comms 
> intercepted. I don't do anything (I don't think so anyway ... and why is that 
> black sedan parked outside? *grin*) that I'm paranoid about.
> 
> Chris...
> 
> 
> 


---------------------------------------------------------------------
Sheffield Linux User's Group - http://www.sheflug.co.uk
To unsubscribe from this list send mail to
- <sheflug-request [at] vuw.ac.nz> - with the word 
 "unsubscribe" in the body of the message. 

  GNU the choice of a complete generation.