C H A P T E R 3

Configuring PPP over Ethernet with NAT

The Cisco 1811 and Cisco 1812 integrated services fixed-configuration routers support Point-to-Point Protocol over Ethernet (PPPoE) clients and network address translation (NAT).

Multiple PCs can be connected to the LAN behind the router. Before the traffic from these PCs is sent to the PPPoE session, it can be encrypted, filtered, and so forth. Figure 3-1shows a typical deployment scenario with a PPPoE client and NAT configured on the Cisco router.

Figure 3-1 PPP over Ethernet with NAT

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4

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5

 

 

Internet

 

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121753

1

Multiple networked devices—desktops, laptop PCs, switches

 

 

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Fast Ethernet LAN interface (inside interface for NAT)

 

 

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PPPoE client—Cisco 1811 or Cisco 1812 integrated services router

 

 

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Point at which NAT occurs

 

 

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Fast Ethernet WAN interface (outside interface for NAT)

 

 

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Cable modem or other server (for example, a Cisco 6400 server) that is connected to the Internet

 

 

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PPPoE session between the client and a PPPoE server

 

 

Cisco 1800 Series Integrated Services Routers (Fixed) Software Configuration Guide

 

OL-6426-02

3-1

 

 

 

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Cisco Systems OL-6426-02 manual Configuring PPP over Ethernet with NAT