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DHCP on a router running PPPoE



I have configured a router to run PPPoE with a DSL router in transparent mode. Here is a brief description of the topology:


DSL Router (Transparent mode)-> Cisco 1841 router running PPPoE-> Cisco 2950 switch (base config)-> PC


The router is running PPPoE correctly because the Dialer interface is getting a public address and it is pingable from the router along with other external addresses. I have configured the router as a DHCP server with the default-router as the interface facing my LAN.

From my PC, I get a valid address from the DHCP server as it should be, but I do not have access to the internet. I cannot ping anything past the default-router.

I have an ACL that allows traffic from my LAN, but does it need to be applied to the Dialer interface. I am at a loss as to why I cannot access external addresses. Any help would be appreciated.


Thank you in advance.




The most common cause is not

The most common cause is not having NAT configured on the router.


Try this. Let's assume your outside interface is f0/0 and internal is f0/1. Your network is


int fa0/0

ip nat outside

int fa0/1

ip nat inside


access-list 100 permit ip any

ip nat inside source list 100 interface fa0/0 overload




HTH, John *** Please rate all useful posts ***
Community Member

Dude, Spot on. I have been



Spot on. I have been working on this for at least 3 days racking my brain. I should always trust the minds on the Cisco forums.


Thank you very much!!!

You're welcome! Thanks for

You're welcome! Thanks for letting us know :)

HTH, John *** Please rate all useful posts ***
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