NB1300 Ethernet Bridge Configuration

[fvalton]

Are more detailed instructions available anywhere than those found in the Netcomm NB1300 manual for the configuration of ethernet bridge support with this modem? Network parameters for the PC that it is connected to in this manner would also be very useful.

[onga]

Umm, the instructions are brief for changing it to bridge mode as they are all you need to change it to bridge mode...

As for network "parameters" I gather you mean the setup of the PC's network card that connects to the modem?

I don't own one of these modems, but I have walked through with a friend getting one going in this way.

Firstly, if the modem HASN'T assigned you a dhcp address of something like 192.168.1.x, then perhaps you should set it. So if this is the case, set the IP of the directly connected network card to 192.168.1.2 or higher. 192.168.1.1 is the modem's IP.

Subnet: 255.255.255.0 or /24, but I presume you are using something like Windows XP to set this up, so the mask is fine. You don't need to set a gateway or a DNS server on this IP.

Now, if you aren't using Windows XP, or another Windows that has a PPPoE client built in(?), you'll need to get a PPPoE client to use this modem in bridge mode, as an ethernet modem. I am not sure if the modem comes with a PPPoE client or not on a CD. You tell me. And once you have a PPPoE client....

You should be able to setup PPPoE on that network interface now, with your nb1300. Your PC will get the static IP now and won't be firewalled by the modem.

If you were talking about "network parameters" on the modem.. you shouldn't have to change anything bar what it tells you. and if you have, maybe you hsould reset the modem to defaults before changing it to bridge mode just to make sure you've done it right.

[fvalton]

Managed to get the modem configured and working correctly as a bridge a couple of days ago - your instructions are correct, thank you.

I had two problems with my setup in fact:

1) Wasn't using a cross-over cable (though this was specified in the instruction manual).
2) Was using Linux Mandrake's built-in pppoe tool, which connected successfully but did not grab the ISP-assigned IP address (strange), which for me is the whole purpose of using a bridge. This was rectifed by changing over to rp-pppoe, which is much cleaner to use and works.

[onga]

Originally posted by fvalton
Managed to get the modem configured and working correctly as a bridge a couple of days ago - your instructions are correct, thank you.

I had two problems with my setup in fact:

1) Wasn't using a cross-over cable (though this was specified in the instruction manual).
2) Was using Linux Mandrake's built-in pppoe tool, which connected successfully but did not grab the ISP-assigned IP address (strange), which for me is the whole purpose of using a bridge. This was rectifed by changing over to rp-pppoe, which is much cleaner to use and works.

Excellent, glad to hear it.

I didn't realise you were using a linux, and yes RP's implementation works pretty well; It might be worth noting that if you're using a router as a NAT for other machines, then you may wish to lower the mtu on the other machines to account for the pppoe overhead. For windows machines, DrTCP does this easily, for Linux or unix machines, just use ifconfig and set it in your startup scripts. for internal lan machines (not the router). Without doing this you may run into troubles on nat'd machines. The mtu for the dsl should be at 1492, to account for the 8 byte over head there, and for other machines on the lan, something less than 1492 is what you want, I tend to go with 1412, but it doesn't have to be that low.

-Geoff

[craigh]

Probably not much use now that you've got it working but...

The NB1300 also has "half-bridge" mode, where it will do the PPPoE dial up but doesn't do any NAT i.e. once it's connected it acts as a bridge. Of course before you can set it up you need to know what your WAN IP address is (remember they're static on Swiftel), but you can do that pretty easily by first setting up the NB1300 in normal (non-bridged) mode and browsing to a site that will tell you, like http://www.my-own-ip.com or http://www.lagado.com/proxy-test.

Another alternative is to not use bridged mode at all but put your web/ftp/mail/whatever server in the DMZ, which is kind of the best of both worlds - you keep your local IP address, you don't have to do any port forwarding (for that one machine), and any other machines are still protected by NAT (as far as it goes).

Personally I find it much more convenient to let the NB1300 do the PPPoE stuff, mainly because your connection isn't reliant on one particular machine being up, but also because you then only have to worry about your NIC settings and don't have to stuff around with PPPoE.

Of course, this isn't meaningful if the machine doing the dial-up is also the firewall and/or router...

[aheydler]

craigh,

Any chance you could outline the settings for putting the nb1300 in "half bridge" mode?

I want the login to happen on the nb1300 but I don't want any NAT. That will be taken care of by the VPN router. I know I can get the VPN router to do the login.... would just prefer to have the login done by the modem.

TIA

Andreas

[craigh]

In the Misc Configuration page there's a setting called PPP Half Bridge.

It's documented in the "Securing your NB1300" document in the Support->Downloads section of the NetComm web site.

[aheydler]

Thanks for that

[aheydler]

craig... (or anyone)

Just to let you know what I did & what is happening in case you have any other suggestions.

I set the nb1300 to operate in normal NAT mode (ie. what it is setup to do now).

I noted the static ip address for ppp1 from the route table page.

I changed to half bridge mode on the misc configuration page.

submitted & saved etc.

I then changed the IP address on my nic to the static ip address noted earlier, ie. what I would expect the wan port on the modem to be.
I also changed the default gateway to point to the modem.

At this stage I would expect my PC to be connected to the WAN.

However I cant get any responses to ping, traceroute, host etc.

Not sure what I have done wrong or where to go to from here.

Any help appreciated.

BTW I am running Linux on the PC.

Just had a thought... Do I have to change the MTU on the PC?

[aheydler]

Played around a bit more....

Tried various values for mtu.

If I ping the default gw I can see traffic on the WAN bit I don't get a response back to the PC.

Tried various combinations for the routes on the PC. I am presuming that since ping data appears to be going out on the WAN that the route settings must be correct. ie. the WAN activity light on the modem blinks in time to the normal ping period.

Of course if I go back to NAT mode everything is OK.

[craigh]

I've never actually tried half-bridge mode myself. I just put my one server PC in the DMZ but leave the NB1300 in NAT mode.

I'll have a play around later and let you know how it goes.

[aheydler]

Craig,

Thanks for that. In thinking about it I may have missed a fundamental point.

In half bridge mode the LAN port on the modem takes the public IP address assigned by the ISP - correct?

If so, the PC connected to the LAN port also needs an IP address in the same subnet but different to the IP address of the modem.

Andreas

[craigh]

Not Happy Jan!

I tried setting it up, and couldn't get it work, so I pressed the reset button to take it back to factory defaults. I am now the proud owner of a stone dead NB1300 and am using a dial up account to post this.

I don't agree that you would need a different IP address on a the same subnet. It is "bridged", so the modem is effectively transparent and your PC is "directly" connected to the internet. If you set it to a different IP address there is a chance that you will be using someone elses address.

I tried every combination of IP address, subnet mask and gateway I could think of, to no avail, and I wasn't even able to contact the NB1300 in the end.

I found a thread regarding this issue on Whirlpool (http://forums.whirlpool.net.au/forum-replies.cfm?t=86458) where the person said to change the WAN type to "1483 Bridged IP LLC". After that the NB1300 was effectively dead, after both a reboot and remains dead even after a reset.

In hindsight it was foolish to have tried something when the documentation is so vague, but the last thing I expected was for it to die completely.

Sorry if I've caused anyone else any problems by mentioning half-bridged mode.

Now if anyone knows how to revive a dead NB1300 without having to send it back to NetComm I'd be forever grateful...

[aheydler]

Craig,

Sorry to hear about your modem.

I appreciate your efforts in trying to help answer my question.
In the light of your experience I wont be pursuing this any further.

Thanks again for your help

Andreas

[influxus]

apparrently a few returned nb1300 have had a jammed reset switch. If the modem is totally dead after reset i'd see if the reset switch is wedged.

[craigh]

Thanks for the suggestion, but can you define "totally dead"?

The reset switch has worked on a couple of other occasions several weeks ago. It has the symptoms I've seen mentioned on Whirlpool related to changing to half bridge mode - PWR and RDY lights hard on, no WAN lights, LAN lights apparently working.

And how does one un-jam it if it's jammed?

[influxus]

Sorry,
when you said it was stone dead i assumed that it was totally inoperative. But if the LAN lights are working then no idea what is going on.

Is the following at all related?

http://kb.netcomm.com.au/messages/619/1616.html?1051152333

[craigh]

Sorry for the hyperbole, I should have said "frozen" or "unresponsive".

The giveaway for me is that neither the RDY nor the LNK lights flash when it's powered up, meaning that it isn't even looking for sync. The RDY is hard on and the LNK and RXD are always off. The LAN lights are on if there is an ethernet cable plugged in otherwise off. If you ping it the ACT light dips, but I suspect that these lights are driven by the hardware, not the software.

If I was to take a guess I'd say that the software loses the plot somewhere very early in the boot sequence, such that it isn't even looking at the reset button anymore.

I'll try the solutions from the NetComm page but I'm not holding my breath.

[craigh]

Picked up a replacement from NetComm this afternoon (260 km round trip for me). It has firmware version 5.005.6b, let's see if this version can do half-bridge mode...NOT!

BTW, NetComm's support was excellent, I got a call first thing this morning after sending an email last night, and could have picked up the replacement at lunch time.

[equinoz]

aheydler, if you are using linux, then i suggest you set your modem to "1483 Bridged IP LLC", enable the 'Bridge', delete all the login information from your modem, and use your modem as a normal modem, not as a router. for you to be able to connect to WAN, download RP (Roaring Penguin) http://www.roaringpenguin.com/pppoe/ and follow the INSTALL/README section.