I am having difficulty connection an ASUS RT-N56U router to a Vigor 120 modem. When I connected the two devices for the first time I opened a browser windows and
the router configuration wizard automatically started to initialise and configuer the modem connection but once this had finished all I got was a "Not Connected" status and
the modems internet light remained off (ADSL light was on and ACT light slowly flashing on/off). I then went into the routers internet settings to configure the two devices manually
but found that the router had auto-detected my ISP's access data (BT) and all acces data was correct (PPPoE, username, password etc). However, still no internet connection.

The 120 is plugged into the routers WAN port but will not connect to the internet. Initially, I disconnected the router from the Vigor 120 and plugged it directly into my PC so that
I could check the modems settings/status and all seemed as it should be (PPPoE/PPPoA enabled). I then plugged the modem back into the router but the internet status was still
"Not Connected" (cannot connect to the remote device) and the Vigor 120 Internet light was still out. Out of desperation I once again plugged the PC directly back into the Vigor 120
but then found that I couldn't even connect to the modem via my browser on IP address 192.168.2.1 !

The router seems to know that the Vigor 120 is there but the 120 will not connect to the internet (eventhough the ADSL light is on).

Any helpful advice would be much appreciated, Happy Christmas.

The internet light isn't used on the Vigor 120 - if it's not working though, and is saying cant connect, I think the first thing to always check is whether you've got a Service Name set on the router, that can make it not find the modem
Also, try factory resetting the modem by holding in the reset pin for ~5 seconds til the ACT light flashes.

Voodle wrote: The internet light isn't used on the Vigor 120 - if it's not working though, and is saying cant connect, I think the first thing to always check is whether you've got a Service Name set on the router, that can make it not find the modem
Also, try factory resetting the modem by holding in the reset pin for ~5 seconds til the ACT light flashes.

Thanks for the post Voodle.

What do you mean by "Service Name" set on the router ?

It'll usually be in with the PPPoE settings on a router, if it's set as anything other than blank then the PPPoE discovery can fail

Technojunkie wrote: auto-detected my ISP's access data (BT) and all acces data was correct (PPPoE, username, password etc).

BT doesn't use PPPoE, change it to PPPoA and set the username to bthomehub@btbroadband.com. No password is required. VPI and VCI should be set to 0/38

I found out that the Asus RT-N56U doesnt support PPPoA but apparently the Vigor 120 acts a PPPoA to PPPoE bridge !

I therefore set the WAN connection type on the router as PPPoE but still couldn't get it to work.

However, after scratching my head a while wondering what the problem could be I enabled NAT (I haven't got a clue what it is) and now everything works perfectly.

I have no idea why enabling NAT would make resolve this problem.

I'd appreciate it if someone could please advise if I'm compromising the broadband performance in anyway by enabling NAT and why I can now connect to the internet
with it enabled but not without it.