Re: router as pppoe client in bridging mode

Hi Garry,

Wouldn't using "dialer persistant" eliminate the need for classifying
interesting traffic and always activate the dialer interface to callout?

However as it seems you are suggesting, having the PPPoE client bridge it's
dialer to the ethernet for the end host doesn't resolve things like how does
the server/client perform dynamic address allocation since the host (R2)
would use DHCP, and the PPPoE server (R0) IPCP unless the PPPoE bridge (R1)
can proxy/translate this somehow, as well as proxying ARP requests from R2
and so on.

From the top of my my head, some alternatives which I'm guessing Koen has
discarded as they are relatively straightforward:
1) As Garry mentioned already - have the PPPoE client running directly on
the end host (R2), having the bridge bridging frames with Ethertypes of
0x8863 and 0x8864
2) Reconfig the bridge to act as a router - requiring IP allocation from the
SP for the end hosts
3) Reconfig the bridge to act as a router that performs NAT for the end
host.

Cheers,
Adam

On Thu, Oct 14, 2010 at 5:00 AM, garry baker <baker.garry_at_gmail.com> wrote:

> i dont have a perfectly clear answer for you, but how can the R1 server be
> the client if it is a bridge?
>
> i know it will work if you make R2 the client and let R1 bridge the PPPoE
> packets between the client R2 and the server R0
>
> because i do not see how R1 can be a client and have the bridged traffic
> made interesting to establish the P2P connection to pass traffic for the
> 1.1.1.0 subnet between R0 and R2
>
> in your setup somehow you need to make the arp coming from R2 interesting
> traffic in the bridge group to get the PPPoE encapsulation started
>
> hope that makes sense
>
> i could see this more clearly when i looked at in wireshark and also did a
> debug of the arp traffic that goes away once you have the pppoe client on
> R2, because pppoe doesnt use arp it is p2p circuit
>
> HTH
> garry
>
> --
> Garry L. Baker
>
> "There is no 'patch' for stupidity." - www.sqlsecurity.com
>
>
> On Wed, Oct 13, 2010 at 1:26 AM, <koen_at_koenzeilstra.com> wrote:
>
> > Hi group,
> >
> > Below is a challenge i would like to present to you and hope someone can
> > help me out on this.
> >
> > The task is relatively simple.
> >
> > There are 3 routers in this scenario
> >
> > R0 (f0/0) --- (f0/0) R1 (f1/0) --- (f0/0) R2
> >
> > R0 is PPPoE server
> > R1 is PPPoE client
> > R2 is simulating a server or pc
> >
> > The goal is to have all the public ip addresses configured on R2 and have
> > R1 act as a bridge. R0 should route it's traffic directly towards R2
> (over
> > bridge R1)
> >
> > What i have achieved so far:
> > 1. R1 as PPPoE client
> > 2. R1 as bridge (without PPPoE)
> >
> > The combination does not seem to work.
> >
> > 1.1.1.1 is R0
> > 1.1.1.2 is R2
> >
> > R2#ping 1.1.1.1
> >
> > Type escape sequence to abort.
> > Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
> >
> > *Mar 1 00:02:05.639: IP: tableid=0, s=1.1.1.2 (local), d=1.1.1.1
> > (FastEthernet0/0), routed via RIB
> > *Mar 1 00:02:05.639: IP: s=1.1.1.2 (local), d=1.1.1.1 (FastEthernet0/0),
> > len 100, sending
> > *Mar 1 00:02:05.643: IP: s=1.1.1.2 (local), d=1.1.1.1 (FastEthernet0/0),
> > len 100, encapsulation failed.
> > *Mar 1 00:02:07.639: IP: tableid=0, s=1.1.1.2 (local), d=1.1.1.1
> > (FastEthernet0/0), routed via RIB
> >
> >
> >
> > Here's the config of R1:
> >
> > version 12.4
> > service timestamps debug datetime msec
> > service timestamps log datetime msec
> > no service password-encryption
> > !
> > hostname R1
> > !
> > boot-start-marker
> > boot-end-marker
> > !
> > !
> > no aaa new-model
> > memory-size iomem 5
> > no ip routing
> > !
> > !
> > no ip cef
> > no ip domain lookup
> > !
> > !
> > !
> > !
> > !
> > interface FastEthernet0/0
> > no ip address
> > no ip route-cache
> > duplex auto
> > speed auto
> > pppoe enable group global
> > pppoe-client dial-pool-number 1
> > !
> > interface FastEthernet1/0
> > no ip address
> > no ip route-cache
> > duplex auto
> > speed auto
> > bridge-group 1
> > !
> > interface Dialer1
> > no ip address
> > encapsulation ppp
> > no ip route-cache
> > dialer pool 1
> > dialer-group 1
> > ppp pap sent-username TEST password 0 TEST
> > bridge-group 1
> > !
> > ip http server
> > ip forward-protocol nd
> > !
> > !
> > !
> > !
> > !
> > !
> > control-plane
> > !
> > bridge 1 protocol ieee
> > !
> > !
> > !
> > !
> > !
> > !
> > !
> > !
> > line con 0
> > logging synchronous
> > line aux 0
> > line vty 0 4
> > login
> > !
> > !
> > end
> >
> >
> > Any help is appreciated.
> >
> > Thanks in advance,
> >
> > Koen
> >
> >
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Received on Thu Oct 14 2010 - 08:33:07 ART