🚀 go-pugleaf

Yes, Jeff
Beating James to an answer seems to be quite a feat in here...
(comp.protocols.ppp)  
Ah yes, DHCP relay, now I remember, should have remembered that. 
And you have helped clarify quite a few things... 
But why are all the providers (almost all) implementing this stuff? 
I don't get it.  Can you splain this?   
Quick, before James gets back..
John


Jeff Mcadams wrote:
> 
> Ooh...ooh...I get to beat James to one.  :)
> 
> Thus spake John D Loop
> >But how do you run DHCP except in an environment where the DHCP
> >discovers can propogate?  i.e. an environment where broadcasts can
> >propogate.  Does the Redback intercept these the same as the ARPs
> >[question for me]?
> 
> Yeah, its called DHCP relay...works like a champ.
> 
> >Maybe what you are saying is the Redback implementation solves most of
> >the problems of bridging.  It still seems like a customer can steal IPs
> >and wreak havoc if he can alter the IP assigned under the mask.
> 
> Nope, they can't...it really and truly does work with RedBack.  I'm
> doing it.
> 
> >Would the redback protect against this, i.e.  does it verify the
> >customer is using his assigned IP?
> 
> It doesn't verify explicitely that I'm aware of, but it knows (either
> from RADIUS, DHCP, static config, and probably other options that I'm
> not thinking of off the top of my head) what IP addresses are on what
> "circuits" (RedBack terminology for a PVC or other type of "session")
> and will only send arps for that IP address down that "circuit" so only
> that customer can respond to the arp request.
> 
> >I wouldn't think so, especially if he didn't assign it [another
> >question for me].
> 
> It can learn the assignment by participating in the DHCP relay, or by a
> RADIUS request when the PVC comes up, static config, etc.
> 
> >But you are still stuck with authentication via MAC, right.
> 
> Nope, I can see what MAC someone has on their ethernet card in the arp
> cache, but I never look at that because I have no need to.  It learns
> the IP <-> circuit mapping via RADIUS, DHCP, static config, etc.
> 
> >So it then gets down to the ISP who wants to do things like it is used
> >to doing, like username/password and Radius servers, and this means ppp
> >to them.
> 
> Nope, please don't make the mistake of assuming that RADIUS and PPP are
> in any way inherently linked.  They are commonly used together, but
> there is no reason that this is required.  RedBack AOS can create RADIUS
> requests based on a PVC switching from down to up.  This can be used
> with a RADIUS server to auto-configure PVCs for customers.
> 
> >Redback solved this problem for the ISPs as well by doing the ppp over
> >the E! oh well...
> 
> I agree with James...PPPoE sucks and I won't touch it with a 39 1/2 foot
> pole.  I think he's done a rather competent job of explaining why.
> --
> Jeff McAdams                            Email: jeffm@iglou.com
> Head Network Administrator              Voice: (502) 966-3848
> IgLou Internet Services                        (800) 436-4456