Use PPPoE and DHCP simultaneously

dhcppppoe

In terms of subscriber management, I understand there are two major approaches – DHCP and PPPoE.

I know I'm being very general, so give me some rope.

If using DHCP, RADIUS/AAA will authenticate the user, and then allow DHCP to happen, assign the address, etc. If I'm using PPPoE, the PPPoE session establishes, and the address is assigned via IPCP.

My question is, if I'm using PPPoE, can we use DHCP to assign the address? And if so, how is that address conveyed to the client? Will DHCP choose the address and be sent to the client via IPCP?

Best Answer

According to Cisco, you cannot use DHCP with PPPoE, :

PPPoE is not supported in conjunction with DHCP because with PPPoE the IP address is assigned by PPP.

Juniper has a whitepaper about Understanding PPPoE and DHCP:

The DSL Forum now also allows using IP over Ethernet (IPoE), which is based on DHCP. However, PPP remains the more mature and robust method for providing many broadband services

Related Solutions

Cisco – Broken PPPoE Config

Adding to the other answers... the thing you lack now is an access-list to limit NAT to your inside addresses... if you apply this configuration, I think this should get you going as long as there aren't other subnets routed by this router.

!
interface GigabitEthernet0/1
 ip address 192.168.2.1 255.255.255.0
 ip nat inside

interface Dialer0
 ip nat outside
!
!! You might not need to do this, but just in case...
do clear ip nat trans *
no ip nat inside source list 1 interface Dialer0 overload
!
access-list 1 permit 192.168.2.0 0.0.0.255
!
ip nat inside source list 1 interface Dialer0 overload

I included pieces from Ricky and Brett's answers, which of course are also required.

PPPoE – How does it reach the Radius Server

For your home router to establish a WAN connection to your ISP, a few things specific to PPP must happen first. You may also have to do some research on LCP and NCP.

Check this link below, it may have the answer you are looking for (see the excerpt on PPPoE below): https://infoproducts.alcatel-lucent.com/html/0_add-h-f/93-0098-09-01/7750_SR_OS_Triple_Play_Guide/concepts_PPPoE.html

PPPoE has two phases, the discovery phase and the session phase.•
Discovery: The client identifies the available servers. To complete the phase the client and server must communicate a session-id. During the discovery phase all packets are delivered to the PPPoE control plane (CPM or MDA). The IOM identifies these packets by their ethertype (0x8863).

→ PPPoE Active Discovery Initiation (PADI). This broadcast packet is used by the client to search for an active server (Access Concentrator) providing access to a service.

→ PPPoE Active Discovery Offer (PADO): If the access server can provide the service it should respond with a unicast PADO to signal the client it may request connectivity. Multiple servers may respond and the client may choose a server to connect to.

→ PPPoE Active Discovery Request (PADR): After the client receives a PADO it will use this unicast packet to connect to a server and request service.

→ PPPoE Active Discovery Session-confirmation (PADS) A server may respond to the client with this unicast packet to establish the session and provide the session-id. Once the PADS was provided the PPP phase begins.

• Session: Once the session ID is established connectivity is available for the duration of the session, using ethertype 0x8864. Either client or server can terminate a session.

During the life of the session the packets may be uniquely identified by the client’s MAC address and session-id. The session can terminate either by PADT sent by the client or server or by an LCP Terminate-Request packet.

Best Answer

Related Solutions

Cisco – Broken PPPoE Config

PPPoE – How does it reach the Radius Server

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