LAN Bridging over WAN... Help?

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8 Oct 2004
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Hi Guys,

I call upon your collective expertise in my time of need.

I'm looking to bridge 2 networks across a DSL link (WAN).

LAN A on 10.0.0.XX and LAN B on 10.0.0.XX.

Modems are talking to each other and making a link and from one modem I can ping the other, from on LAN I cannot ping the other, or the other LAN's modem.

Is what I'm looking for feasible without using a VPN or am I in the clouds?

Cheers,

J
 
I have one modem set to 192.168.20.4 as WAN IP and gateway as 192.168.20.22. And visa versa for the other modem.

The connection is set to 1483 IP Bridged.
 
its only going to work if the routers support bridging which is not likley, otherwise a packet sent from lan A that YOU want to go to lan B will NEVER get past the 1st router... as the router will know that 10.0.0.x is its local lan and there is no need to pass it on...

why not route? I assue you have two office already set up and you dont want to mess with the setup?

One modem is a Zoom X5 (cheap and nasty) which supports 1483 Bridged IP + NAT. And the other is an Aware 550 Module, which is uber expensive and supports bridging via xml setup.

I have several paired devices, one at each side and need them to talk to each other, they use several protocols/ports which is why I'm trying to bridge.

More than one device uses port 80 for configuration so routing would cause issues I think.
 
hmm, are you sure you're not confusing the modem bridge that basically ports the WAN IP to the LAN side of the modem (when you want to tack your own router to the otherside of the modem)?

I might be, I'm not hugely experienced beyond plug and play LAN's. Never messed with this side before.

I'm just not sure why you'd be trying to avoid using a site to site VPN?

I only have hardware to do this and not sure how to do it without software.

So should I set up a routing table for the paired devices using MAC/IP's?
 
It seems that is no longer an option. Current hardware, I've been told, 'should' suffice.

But I don't think it's with the cheap modem. The information is mostly coming from the other end anyway.

I'm playing with the expensive modem/router but it's difficult as it's set up from xml files downloaded via ftp, no nice GUI to play with.

One file called co_atm_router.xml is for setting up the mode. I have available modes - Router, Bridge, ExpressBridge and PPP. I can't see anywhere in these files for forwarding any LAN information on the WAN, so I'm assuming it would need to be set-up as some sort of transparent link so that information will always be put across the whole LAN.
 
At what point does the person telling you the existing hardware will "suffice" accept you are wasting time?

When it catches fire and I'm standing with a box of matches and a bottle of paraffin.


If you only have modems (not routers), and you can't use a leading edge server/software or purchase VPN routing hardware, then you might as well just give up now.

They are both routers. They have DSL links and Ethernet. But yes, not extra hardware available. Is it even possible?
 
Ok, so maybe I've not included all the details.

This is NOT a standard network setup. They are devices inside subsea equipment and alternatives cannot be used due to the integration of other hardware.

I have got something working now, not sure how but I have. I've configured each device to use the LAN IP of the local router as the gateway, this seems to work as information is now being forwarded. There are still a few bugs which I'm stomping. It is still most confusing.
 
In the offshore industry people refuse to change equipment for many years, sometimes decades. So if I need to use a specific product, an alternative may not be available, if it has specific hardware for IP integrated into it it's not always possible to swap out for something nice.

Sometimes you just have to use what you've got.
 
What i wqas suggesting is that if you were going to get VPN to work (and general best practice really) you shouldn't have two LANs with the same IP address range. So just changing one of them to 10.1.0.0 or something instead of 10.0.0.0. Might work while you're port forwarding but could cause major problems in the future. Like all potential issues, better tackled sooner rather than later because it'll only get more difficult.

In order to get it to work I did need to set one end to 10.0.0.xx and the other to 10.0.100.xx.


Really you need to use a module on the surface to do the client side equivalent of the Aware module. This will simplfy things a great deal and essentially bridge the system which is really what you're looking for (so your device is ethernet > DSL bridge system > ethernet, where the DSL bridge system is completely transparent)

You are correct in your assumptions, but how would I achieve this? Set the Aware to a bridge/router and the Zoom to 1483 bridged IP?

Speak to the supplier of your subsea kit, they will almost certainly be able to suggest something.

The supplier has the exact same modem at the top end but has a PC at their bottom end which they remotely log into to set things up (and no, unfortunately this is not an option for my setup).
 
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