Full Bridge ADSL

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skaffen

14 posts

Geek

#22354 25-May-2008 12:06

Hiya

Can someone recommend an ADSL modem that'll do full bridge mode? I'm wanting to bolt some ADSL onto a firewall appliance at work.

Cheers

chriswiggins

413 posts

Ultimate Geek

#133939 28-May-2008 19:34

I dont know about full bridge - what do you mean?

I know that the DSL-502T Gen 2 does half-bridge. I am currently (paused for a while) setting up a smoothwall firewall with this.

skaffen

14 posts

Geek

#133957 28-May-2008 19:53

I want a fully transparant bridge - so it dumbly forwards everything from the ADSL to the ethernet port, and vica-versa.
That way I'm effectivly bolting ADSL onto the Firewall appliance. The firewall has all the requisite settings for PPPoA and PPPoE, just no ADSL Layer 1.

I've found one now anyhow, I just have to win the auction on Trademe

Thanks for the info

rphenix

985 posts

Ultimate Geek

Lifetime subscriber

#135480 4-Jun-2008 16:39

if your using Xtra or an ISP that resells jetstream your wanting basically a modem that converts PPPOA to PPPOE (unless your on clear in which case you can actually use PPPOA in bridged mode).

There is one modem the "Draytek Vigor 110" which provides a true PPPOA to PPPOE bridge and is cheap too :) unfortunently not available via the normal NZ supplier (Snappernet?) yet. However thats about to change but if you cant wait buy one online and import it yourself will cost you around $110.

cisconz

cisconz
1341 posts

Uber Geek

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#135590 5-Jun-2008 07:56

rphenix: if your using Xtra or an ISP that resells jetstream your wanting basically a modem that converts PPPOA to PPPOE (unless your on clear in which case you can actually use PPPOA in bridged mode).

There is one modem the "Draytek Vigor 110" which provides a true PPPOA to PPPOE bridge and is cheap too :) unfortunently not available via the normal NZ supplier (Snappernet?) yet. However thats about to change but if you cant wait buy one online and import it yourself will cost you around $110.

The Draytek 2700e does the same thing and is available now.
A bit more expensive however.

Hmmmm

olof

154 posts

Master Geek

Trusted

One NZ

#135956 6-Jun-2008 12:34

Many many modems support bridged modem. (Routed mode is default obviously for Telecom and all of the UBS re-sellers.)

For example, my modem at home, a simple Dynalink RTA1320, can be put in bridged mode by a tick in a box. (Never tried it though.)

You are of course aware that this turns off NAT etc and this will now have to be configured on your firewall.

Olof Olsson - my views are my own.

rphenix

985 posts

Ultimate Geek

Lifetime subscriber

#136045 6-Jun-2008 18:26

olof: Many many modems support bridged modem. (Routed mode is default obviously for Telecom and all of the UBS re-sellers.)

For example, my modem at home, a simple Dynalink RTA1320, can be put in bridged mode by a tick in a box. (Never tried it though.)

You are of course aware that this turns off NAT etc and this will now have to be configured on your firewall.

Olof thats not quite what you think it is. Your probably thinking of Bridged IP over ATM (RFC 1483) thats not gonna work with Jetstream however it can with TelstraClear.

very few adsl "routers" often incorrectly termed as "modems" support PPPOE to PPPOA bridging. Infact the draytek 100 or 110 would be about the only current modem around today (ie ADSL2 compliant etc..) that is a true modem in all senses and not really a router.

Half bridge mode, or IP extension (or the many variant names on the same thing) isnt too bad on some routers like the US Robotics 9105 worked reliably. It's also a lot more common even the cheap free DLINK 302G that Xtra used to give away worked in half bridge though not as reliable as the USR.

olof

154 posts

Master Geek

Trusted

One NZ

#136109 6-Jun-2008 23:35

rphenix: point taken. You are absolutely correct. My Dynalink will do full bridging, but only if the WAN interface is PPPoE. It cannot do PPPoA/PPPoE bridging. Of course, all Telecom NZ and other ISPs using Telecom's network is using PPPoA... TelstraClear also uses PPPoA when re-selling Telecom UBS, but we use PPPoE for most of our own ADSL services.

Olof Olsson - my views are my own.

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webwiznz

4 posts

Wannabe Geek

#137848 13-Jun-2008 17:27

I have recently spent a good deal of time playing around with this, setting up a debian etch box as a gateway.

Some of what i learnt along the way is on the WLUG wiki uner ADSL.
http://www.wlug.org.nz/Half%20bridge%20with%20PPPoA
http://www.wlug.org.nz/Billion7100

In brief: as said above on telecom derived isps, full bridge is out.
What you can do is:
- wait for the vigor 110.
- Use PPPtP with the old speedtouch modems. (turn off the encryption)
-(try) half bridge, which many cheap modem/routers have. In my case this yeilded mixed results.

With a billion modem, Xnet, a copper line, in the King Country it works like a charm. You do need a hack to get Linux to work with the half bridge.
My attempts to repeat that setup in Auckland two weeks later on a roadside cabinet using Planet, and the same hardware as above, showed very unstable results. If you want to know more about this ask me. In the Auckland environment, i settled for the 1:1 NAT+DMZ solution descibed in the refs above. It seems stable, been up for 3 days, serving approx 25 workstations, doing ip accounting and access control.

Theres my thread on NZLUG, here:
http://www.linux.net.nz/pipermail/nzlug/2008-April/012602.html

which also mentions a guy who knows someone who is bringing the Vigor 110s into the country for release any day.

HTH, and if anyone can shed any further light on the variation of half bridge, do chip in.

Peter

webwiznz

4 posts

Wannabe Geek

#137849 13-Jun-2008 17:31

Oh, and could the OP please reply with what they bought and how it went.

webwiznz

4 posts

Wannabe Geek

#137852 13-Jun-2008 17:39

One more thing, 1:1 NAT+ DMZ.

This reduces the NAt load on the modem/router down to almost nothing. It basically maps the public WAN IP direct to one singel LAN address, that of your gateway box/ wireless router. Then you turn on DMZ, using the sam LAN IP as above, which effectively bypasses much of the firewall built into the modem and forwards all ports to the gateway box. The advantage is you at least have a static IP on the gateway. Which makes some things easier like firewalling. The disadvantage: dont know. I dont have the ability to measure performance accurately enough to say, if its less efficient than half bridge.

However what i do know is that the half bridge thing is a nasty old hack. You dont actually get the WAN IP on your gateway, just a pretense of it, via the dhcp server running in the modem. Its actually really crude. The modem passes you a fake gateway address, fake netmask, and super fast lease renews. Windows can seem to accomate the mes, but linux and many wifi routers just get really confused. The better wifi routers have generally released updated firmware to cope with it.

P.