[cisco-bba] PPPoE with Routed Subnet

[Frank Bulk]

Brian is basically suggesting that the service provider route the /29 via
the IP address the PPPoE client obtains.  That means the customer has an
outside (PPPoE) and inside (/29) interface.

I haven't tried bridging, but I would think it's possible to have the
service provider's RADIUS server hand out an IP address from the /29 block
to the PPPoE client, and then bridge the other IPs in the /29.

I think it would be much more straight forward if you could have bridged
connection or do what Brian recommended.

Frank                   

-----Original Message-----
From: cisco-bba-bounces at puck.nether.net
[mailto:cisco-bba-bounces at puck.nether.net] On Behalf Of Brian Raaen
Sent: Monday, January 12, 2009 6:21 PM
To: cisco-bba at puck.nether.net
Subject: Re: [cisco-bba] PPPoE with Routed Subnet

Patrick,
        If this is like most of the PPPoE setups I have worked with (I work
on the
service provider side of things) you would have a static that is assigned to
the wan of your router using ipip, and the /29 is routed to that
address(think - ip route $subnet 255.255.255.248 $static).  When that subnet
hits your router you can do pretty much anything you want to with it.  We
usually suggest that customers assign the first usable to the lan of their
router (usually ala linksys variety) and make sure that nat(or gateway mode)
is turned off.  They would set up their internal host using an ip out of the
subnet with the router internal as their gateway.  Some customers even add a
second router for NATing (if you are using lo end soho routers that may be
your only option).  Since you are using a IOS powered cisco you can look
into
using something like 1:1 nat to allow you to use all 8 addresses in the
subnet if you want to make sure to use one for pat (i.e. standard nat) if
you
need to.


----------------------

Brian Raaen
Network Engineer
braaen at zcorum.com

On Sunday 11 January 2009, Patrick Wu wrote:
> Hi Everyone,
>
> I have a DSL connection running PPPoE with a routed subnet, the service
> provider indicated that it will use the 1st IP address of the routed
subnet
> for the router (WAN?), and the rest of the IPs of the subnet can be
assigned
> to the hosts behind the router.
>
> What I want to know is whether I need a bridged interface between the WAN
> and LAN side of the router (Cisco877), and what configuration will help me
> achieve this?
>
> Thanks to all!
>
> What I have so far (was doing NAT before, but probably will remove it
> later):
>
> interface ATM0
>  no ip address
>  no atm ilmi-keepalive
>  dsl operating-mode auto
>  service-policy output SIP-priority
> !
> interface ATM0.1 point-to-point
>  description $FW_OUTSIDE$$ES_WAN$
>  pvc 8/35
>   pppoe-client dial-pool-number 1
>  !
> !
> interface FastEthernet0
> !
> interface FastEthernet1
> !
> interface FastEthernet2
> !
> interface FastEthernet3
> !
> interface Vlan1
>  description $ETH-SW-LAUNCH$$INTF-INFO-HWIC 4ESW$$ES_LAN$$FW_INSIDE$
>  ip address 192.168.0.1 255.255.255.0
>  ip nat inside
>  ip virtual-reassembly
>  ip tcp adjust-mss 1412
> !
> interface Dialer0
>  description $FW_OUTSIDE$
>  ip address negotiated
>  ip mtu 1452
>  ip nat outside
>  ip virtual-reassembly
>  encapsulation ppp
>  dialer pool 1
>  dialer-group 1
>  no cdp enable
>  ppp authentication pap callin
>  ppp pap sent-username xxxx at xxxx password 7 xxxx
> !
> ip forward-protocol nd
> ip route 0.0.0.0 0.0.0.0 Dialer0
> !
> ip nat translation udp-timeout never
> ip nat inside source list 1 interface Dialer0 overload
>


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