[OT] Small NAT device ?

Hi,

Does anyone have any idea if there is a product on the market designed specifically to do NAT ?

Ideally, it would be a very small device, and could be added to an existing network segment.....or added inline to a wireless bridge (w/o NAT) to provide NAT?

Thanks in advance,

DanS

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DanS
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DanS wrote in news:Xns986C9017DFC89thisnthatadelphianet@216.196.97.142:

Additional note, since it sounds like I could just be talking about a plain router.

Hoping to find something very small that could be put in-line on a CAT5 run. I'm envisioning a small box, with an RJ on each end and a power connector, not much larger than an inline RJ coupler.

Reply to
DanS

On Mon, 30 Oct 2006 13:48:31 -0600, DanS wrote in :

It does.

Sounds to me like a small wired router. Is size such a big issue?

Reply to
John Navas

John Navas wrote in news: snipped-for-privacy@4ax.com:

Yes, it has to be small. It is to be packaged in with an EVDO modem and a

24v-to-12v converter.

DanS

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DanS

John Navas wrote in news: snipped-for-privacy@4ax.com:

Here, something like this,

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but eth-to-eth with NAT.

DanS

Reply to
DanS

Gumsitx have a daughterboard with 2 Fast ethernet ports that could be used to produce such a device.

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You could ask the gumstix guys if they know of any products being developed

Reply to
developers

snipped-for-privacy@thuk.co.uk wrote in news: snipped-for-privacy@i42g2000cwa.googlegroups.com:

Thank you. I just penned of an e-mail to them.

Regards,

DanS

Reply to
DanS

DanS hath wroth:

24VDC? Is this going on a big tractor or diesel generator?

An EVDO modem would require a serial or USB port to ethernet router. You might wanna look at:

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see if they fit your application. The list of supported protocols on the Xport-AR is extensive, but doesn't appear to include NAT. However, there are 3rd party developers that sell the missing protocols including NAT:
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Also, if you wanna make prototyping easy, you'll need one of these:
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Reply to
Jeff Liebermann

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

I can't really say.

Nope. I've used the X-Port in designs before. The EVDO device desired by the customer is made by Airlink, and has ethernet on it. The ethernet side can be configured like a bridge, and pass the internet IP onto what ever device is connected to it. Or, you can specify a private 192.168.x.x IP for it to DHCP to the connecting device and the Airlink box will do (a lame implementation of) NAT, to that IP. One-to-one NAT only, just to that one single IP it DCHP's out. So it could hand out that one IP to a router device, and the router device NATting the wireless clients to that IP.

Originally we were looking at using the Senao/Engenius outdoor AP (NOT my idea), but as it turns out, those do not do NAT when in AP mode (?). I know, they are sold as bridges, but ........

I have been unable to find a similar small AP Router w/NAT and POE...any ideas ?

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This is VERY interesting...and HOLY SH*T...6.1 miles from my companies head engineer's location in AZ. Not that I think we would even think of using the X-Port here, but he just eats this stuff right up.

Here's an interesting device. I ran across this device from RAD in my current quest. It's called tiny router, and is essentially a full router in a slightly oversize DB25 shell. One side is ethernet and the other is your choice of V.24, V.35, V.36, RS-530, X.21; internal fiber optic or 4- wire modems....which is why it's a no-go for my application.

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X-Port not included. We've got a bunch of the X-Ports and proto boards already.

Thanks for taking the time to respond.

Regards,

DanS

Reply to
DanS

DanS hath wroth:

Ok, it's probably military. Don't worry. Nobody reads usenet news any more so you're secret is safe.

This one?

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Perhaps you're using the wrong Airlink model? See:
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"For more advanced network requirements, the Raven-E also provides an option for either public or private IP (NAT), GRE/IP-SEC pass-through, and SNMP management."

I was reading the (Verizon EVDO) manual at:

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found a similar description of NAT operation on Pg64 if the "private IP mode" is selected. However, it seems that it only does

1:1 NAT in this mode. In the "public network IP mode", it apparently will do normal NAT with DHCP IP address delivery from the internal DHCP server. See Pg24.

Yech? All bridges should pass broadcasts, which are necessary to pass DHCP requests. Something is wrong (somewhere). Have you tried sniffing the ethernet port on the Senao to see if broadcasts are passed?

Yeah. One of those "travel routers" sold by the commodity vendors. I don't think they'll do PoE, but probably can be powered by a small DC-DC switcher. One of the 78xx switcher plug compatible replacements should work.

Alternative firmware is available if you feel like hacking.

Reply to
Jeff Liebermann

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

No not military !!!! I don't think they would go for 802.11 anything.

Yes it is the Raven.

We have tried all kinds of configurations with this to no avail. Almost 3 days of experimenting. I'm not working on this myself, but helping out the guy who is.

There were some bizarre results. I can't remember the exact details right now, but I do know that in one instance, the Raven handed out the same private IP to 2 different devices, and it worked, the internet was available !!! We all know it should not have worked.

Maybe I'll have some updated info later on.

Thanks Jeff.

Regards,

DanS

Reply to
DanS

DanS hath wroth:

That was last years military. Today's military is buying COTS (commercial off the shelf) hardware.

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don't forget those rather high power 2.4 and 5.7GHz amplifiers that are allegedly for "military and export" use.

Well, there are quite a few things that run on +24VDC. You've sorta eliminated tractors, generators, and military. It could be avionics, which is not likely because CDMA/EV-DO systems don't work very well at altitude. They hear too many cell sites. The baseline noise level creeps up to the point where the receiver goes comatose and the handset spends all its time trying to handoff to the strongest cell site.

There's not much left. Solar power installations are sometimes 24VDC. Some SCADA stuff runs on 24VDC. Powered shipping containers sometimes use 24VDC. However, none of these have a size constraint, which leaves me baffled. Got any more clues?

Try again. The docs clearly state that it supports DHCP IP delivery which implies a functioning NAT. It should work in the "public IP network mode". The description you gave of 1:1 NAT is very obviously the same as the "private IP mode".

Oh-oh. I've seen the problem with mobile IP. Also check if the router hands out its own IP address. That problem comes from setting the DHCP server to deliver the entire /24 IP block and with ping disabled. If the DHCP server can't ping itself, it thinks it's own IP address is available.

It's actually fairly easy to create a situation where two devices, with different MAC addresses, get assigned the same IP address. All that's necessary is to have very long DHCP lease times, have one device disappear, and power cycle the router causing the DHCP lease table to clear. What is suppose to happen under these circumstances is that the router trys to ping the IP address before an IP gets re-assigned. If the device is gone, DHCP will happily give it to some other device that's present. When the old device, with the previous IP address, reappears, it should immediately request a DHCP renewal, get rejected, and start over requesting a new IP address. However, this process only starts at 50% of the lease time. If the lease is too long, it will not request a lease renewal, and will merrily try to use its original IP address. If your EVDO modem gets power cycled often, I suggest you use the shortest possible DHCP lease time to avoid the problem. The only reason we don't see this effect too often is that most home and office router are not power cycled regularly.

Hmmmm... intermittent power. That makes it a +24VDC vehicular application as all the others have constant power. You're setting up a networked mobile gambling operation in the back of a semi tractor trailer and using the EVDO modem for the backhaul.

More clues?

Reply to
Jeff Liebermann

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

Actually I was mistaken about the DC converter, and that was for the Engenius/Senao gear, which takes a 48VDC power supply on it's POE injector. It doesn't even work if you inject 24 Volts. So the vehicle this is supposed to go in is actually 12 volt, not 24.

More info Jeff is that I just set this up again. This time, the Raven was set to use a global addressing scheme. The AP and client (external client connected to a PC through a x-over cable), not a PCMCIA card, were configured @ 192.168.1.x. There was a WLAN connection between the 2 wireless devices. The PC was static on that 192.168.1.x subnet to verify operation of the AP/Client.

The PC was then set to DHCP, and it DHCP'd a global 70.7.x.x global IP and the PC had internet connectivity thruough the EVDO network. I assumed this would work because the AP and WClient are bridging, not routing. Another PC/client setup was added. The PC initially on the 192.168.1.x subnet, to verify connectivity through it's client to both the AP and the other client.

The second PC was then changed over to DHCP, making this the second PC on the network trying to DHCP from the EVDO device thru the off-subnet wireless. The second PC did not get an address and after about 30 seconds, I released the IP on the first PC, and just a few seconds later, the second PC was assigned a new IP, the same the first one had.

It's apparent that there can never be more than one IP used with the Raven device w/o using a router connected directly to it, be it a limitation of the Raven itself, or of the Sprint network, I don't know. All of the documentation for it also constantly refers to 'the connected device' and never uses a plural form.

On to the other topic.....yo posted a link to that Asus travel router. That is nice and small, but will not work in this application. The issue is that it has an external antenna, with a connector. Unless the AP has a built in antenna, like the Senao/Engenius gear, it would need to have a coax run to the antenna, minimum I think would be around 10 ft. Since this is not a high powered device, 15 dbm out, any coax loss would be huge, proportionally.

Are you familiar with the Senao/Engenius AP I am talking about ?.....

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It's an all in one with POE meant for outdoor use, and in the picture it looks larger than it is in real life.

Thanks again for the discussion, we may be able to hammer something out.

Regards,

DanS

Reply to
DanS

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