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FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

plaid
Newbie
Posts: 4
Registered: 11-06-2012

FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

Hi All,
I currently have two broadband connections, one with Be (ADSL2+) and one with Plusnet (VDSL/Infinity).  I have 8 IPs with the Be connection and have the Be modem configured in bridge mode.  This means that assigning an external IP to a device is as simple as connecting a network card to a switch that is in turn connected to the Be modem and then assigning the external IP to the network card.  The Be modem simply passes incoming IP packets on to the network card with the external IP.  It's very flexible and I think the fact that Be use PPPoA makes this possible.
I'd like to be able to do the same thing with multiple IPs on the Plusnet connection.  After a lot of searching I've found references to getting a modem running in half bridge mode.  This means that the modem will negotiate the PPPoE connection and simply forward the incoming packets onward to devices connected to it.  At the moment, I have a Linux box negotiating the PPPoE connection which means that only this Linux box gets the external IPs.  I could possibly do something with some bridges and proxy ARP to hack together something that acts in much the same was as a modem a half bridge but it wouldn't be as easy to work with as having modem do it.
Has anyone done anything like this with a BT Infinity connection?
7 REPLIES
Community Veteran
Posts: 6,394
Thanks: 511
Fixes: 46
Registered: 30-07-2007

Re: FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

Assuming you have the standard plusnet supplied tg582 router , have a look here http://www.google.co.uk/url?sa=t&rct=j&q=tg582n%20transparent%20nat&source=web&cd=1&cad=rja&ved=0CDM...
I'm pretty sure you can make the tg582 do what you need if you're happy with configuring it from the CLI.
plaid
Newbie
Posts: 4
Registered: 11-06-2012

Re: FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

Quote from: MisterW
Assuming you have the standard plusnet supplied tg582 router

I've got a BT Inifinity connection so I'm using the Echolife HG612 VDSL modem and the supplied Netgear router.  The TG582 is an ADSL2+ modem router.
That's a very interesting document though, thanks!  I'll need it when I set up my wife's new Plusnet connection in her office.
Edit: Or do you mean I should plug the Echolife into the TG582, use the Echolife as the modem and the TG582 to negotiate the PPPoE connection and then use that CLI magic to proxy ARP the IPs to the LAN interface on the TG582?
Estragon
Rising Star
Posts: 811
Thanks: 10
Registered: 07-02-2012

Re: FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

This is very confusing  Huh
As a side-issue, Infinity is a BT Retail product, corresponding to Plusnet's two fibre packages.  You are not on Infinity, nor are you on VDSL.  It is VDSL2.
The 582n supplied for Plusnet fibre has a modified firmware to change LAN port 4 to a WAN port.  So on fibre it is acting as a cable router, not an ADSL2+ modem/router.
The Echolife modem is a modem/router locked down to bridge mode. It is possible to unlock it, (not easily), and I expect you could then do what you want. Or if you get one of the Huawei equivalents, those are easily unlocked.
Have a read of this recent thread on the tbb forums. His and your wants seem identical to me, so it might be worth asking the OP there how he is getting on.
Community Veteran
Posts: 6,394
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Fixes: 46
Registered: 30-07-2007

Re: FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

Quote
Edit: Or do you mean I should plug the Echolife into the TG582, use the Echolife as the modem and the TG582 to negotiate the PPPoE connection and then use that CLI magic to proxy ARP the IPs to the LAN interface on the TG582?
That's exactly what I meant, as I assumed ( wrongly ) that you had the PlusNet supplied TG582 for FTTC. As Estragon says, this has modified firmware to disable the ADSL port and use LAN port 4 as a WAN port. Its even possible to configure the standard TG582n ( ADSL firmware ) to use port 4 as a WAN port using the CLI. However since you've got the earlier supplied Netgear router none of that applies.
plaid
Newbie
Posts: 4
Registered: 11-06-2012

Re: FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

No problem, I'll get a TG582N from eBay and see if I can get it to do what I need.
Estragon
Rising Star
Posts: 811
Thanks: 10
Registered: 07-02-2012

Re: FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

Quote from: MisterW
As Estragon says, this has modified firmware to disable the ADSL port and use LAN port 4 as a WAN port.

Smiley
I didn't say the ADSL port was disabled.  I would expect it still to be available for ADSLx usage. (Obviously not used concurrently with an FTTC service).
That's just a guess though.
Community Veteran
Posts: 6,394
Thanks: 511
Fixes: 46
Registered: 30-07-2007

Re: FTTC Service with Modem in Half Bridge Mode? (Assign External IP Direct to PCs)

Disabled in firmware is what I meant really. I would guess it's not physically disabled. From my experimenting with the CLI and a standard ADSL TG582n, its posible to reroute the internal 'Internet' interface from the dsl(atm) connection to a ppp connection via a LAN port. My guess is that the modified f/w does this by default. You could probably do the reverse using the CLI with an FTTC f/w equipped unit.