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Draytek 2820n & 2 PPPoA ADSL 2+ connections

  • kwiksand
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18 May 2010 19:12 #62059 by kwiksand
Hi,

I've been using my Draytek (WAN1) for a month with the first DSL connection (BT Business), and have just had my second DSL connection installed (OPAL Business). Much to my delight they're both PPPoA, and of course the 2820 will only connect to PPPoA enabled DSL on the first WAN link.

Whats the best method for setting up the other connection, I'd rather not use Double-NAT between the 2820 (WAN2 port) another DSL modem/router, is there a set of routing rules I can use on the draytek that I can use to connect to the second DSL with NAT off?

The DSL connections are:
- BT Business ADSL2+ - PPPoA Static IP
- OPAL Business ADSL2+ - PPPoA Static IP

Coming from Australia PPPoA is something I've only seen once or twice as we use PPPoE pretty much accross the board there.

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24 May 2010 16:42 #62110 by wiggum
Replied by wiggum on topic Draytek 2820n & 2 PPPoA ADSL 2+ connections
Hi,

I have a very similar question but perhaps am not as knowledgeable as kwiksand here. Basically, I have two UK, PPPOA ADSL connections at a site. One of these is fed into a media converter and linked to another comms unit via fibre. Unfortunately, as we have only one fibre link, the second connection is doing nothing. I have a Vigor 2820 here and planned to use that for both connections though now realise I can't put two PPPOA connections directly through this router.

The two routers already onsite are Linksys WAG54G2's. Is there anyway for me to get this up and running with the kit I have?

Thanks in advance!

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24 May 2010 18:51 #62112 by kwiksand
Replied by kwiksand on topic Draytek 2820n & 2 PPPoA ADSL 2+ connections
I'd say we're in exactly the same boat then.. Seems strange I've(we've) not had much help on the Draytek forums though! I think the answer is fairly simple.

Firstly, it appears there's three options:
- Half Bridging (also called DHCP Spoofing, IP Redirection and ZipBR) depending on manufacturer's buzz word. This is where the modem does the PPPoA authentication but passes its external/internet IP off to the 2820 like there was no authentication required. (models include: Linksys AM200, AM300, Netcomm LTA1320, most of the Speed touch series, Zyxel pr-660D, etc)

- PPPoA -> PPPoE pass through (supported by the Draytek1xx series) where the modem handles the PPPoA part of it and allows for a PPPoE device behind it to authenticate as if it were a PPPoE connection (This seems like the most elegant solution with our Drayteks, as the 2820 then does all the authentication for both connections) (many Cisco and other high end models, Draytek 1xx series)

- PPTP -> PPPoA forwarding uses some form of the above via a shared VPN connection (Many slightly more expensive PPPoA routers, though I know nothing about this method)

- Double NAT'ting - What I'm trying to avoid, where the modem itself does NAT and pushes all data through to a DMZ host (the 2820 behind the it), and then the 2820 will have to NAT again. (Basically any/every router which support PPPoA will do this)

I'm not completely sure, but I dont think the Linksys' you have support half bridging so you'd be stuck with a double NAT solution (easy enough, set the linksys with DHCP off, then:
- Set its local IP (e.g 172.16.0.1)
- Set NAT to on and create a DMZ host (e.g points to 172.16.0.2)
- In the 2820 set its static IP (on WAN2) to 172.16.0.2 and tweak the connection settings (MTU, Keepalive, DNS, etc if required).
That *should* work, but its not the nicest and I wouldn't recommend it for a work place.

Hope this helps, anyone else care to comment?

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24 May 2010 19:38 #62113 by rothers
Replied by rothers on topic Draytek 2820n & 2 PPPoA ADSL 2+ connections
Use PPPoA -> PPPoE passthrough with a modem, no need for anything more complex.

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24 May 2010 21:56 #62114 by kwiksand
Replied by kwiksand on topic Draytek 2820n & 2 PPPoA ADSL 2+ connections
So, which modem would you recommend?

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25 May 2010 09:21 #62117 by wiggum
Replied by wiggum on topic Draytek 2820n & 2 PPPoA ADSL 2+ connections
Thanks for the help kwiksand. I noticed you hadn't many replies for a while too and just this morning found your post elsewhere! :)

I'm actually going out to the site later today and, at the moment, only have the kit mentioned. I was thinking about trying the double NAT setup though, from what I've read, I don't think it will work too well when one of the connections is for an ATA and VoIP phone. :( Might try it initially though.

One question, I wonder if you or anyone else can answer, is how this will pratically work in my scenario. If both connections are on the same subnet and, if I'm patching both of these via a single fibre link (so, one CAT5E cable coming out the other end then into a switch) on the end-user devices, how do I differentiate between the two ADSL connections. If they were on different subnets, I guess I would just manually give the devices an IP address on the relevant subnet but, with them both being on the same subnet, I can't make sense of it in my head.

Thanks again.

Edit - Alternatively, is there a Dual WAN Draytek that will take x2 PPPOA ADSL connections?

Edit again - Ok, I've found this page http://draytek.co.uk/products/vigor2920.html that shows the setup I am trying to achieve:



so my question again relates to the scenario of the fibre patching. I assume, if I follow that setup, WAN2 on the Draytek will be set to PPOE. So should the ADSL logins be input there, or on the seperate Draytek modem?

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