I am trying to set up a consumer-grade 4port router for a client who has DSL, and the router is asking for PPPoe login information.

My question is: What would the router do with that login?

As I understand it, the DSL modem will acquire the IP address with the login, and the router would get the IP address from the modem using DHCP...correct?

DSL requires a software client installed with that information provided.

By entering this software into the Router, the router will maintain a constant connected status with the DSL. Generally, you have to connect to DSL via the software client before you can use the internet. The router will maintain this connection as an always-on connection.

Thanks for your reply, I'm starting to understand more. I feel very ignorant here, the reason being that I have only connected routers to cable modems, never DSL till now, but unfortunately the client doesn't know how it got configured in the first place. Do DSL modems accept login credentials also, or do they only pass through credentials that come from a pc/router behind it?

I have a problem I am absolutely pulling my hair out over. This client has a combo DSL modem/router with 4 ports, and connecting a computer I am able to get an IP and access the internet... however, if I put a wireless router (with auto MDI/MDI-X) in between, my computer is able to get an IP from the wireless router, but can't access the internet. Remove the wireless router and the computer can access internet just fine again. Problem persists even after entering DSL credentials into the wireless router. Do some router brands have problems with DSL connections? (ie netgear, trendnet)

Disable DHCP on the wireless router, set a static IP address and have it point to the router in place. Sounds like the issue you're experiencing.

Routers require configured for use with DSL - someone at some point configured it, most likely a tech installed it for them and did all that. The router doesn't pull information from the computer - unless in some cases I've seen where the router can use Windows Login information which is never how its done anyhow.

You need to manually enter the username and password into the router.

The wireless router should have a static IP, like 192.168.1.2 (router would be 192.168.1.1).

IP 192.168.1.2
Subnet 255.255.255.0
Gateway/Router 192.168.1.1

Disable DHCP

That will tell the wireless router to forward all requests to the router which will then "Route" the information accordingly.