Double NAT question

[rockymtnhigh]

I was helping a friend put in a new network at the gym he owns. We replaced an old Netgear router and a Wireless G access point with an Airport Extreme router/wireless network. The AE is setup properly and the ethernet-based machines all have net, and the wireless network works fine. But the Airport Utility tells me there is a Double NAT problem.

Airport said the solution was to set the Router to Bridge only, but when I do that I lose all internet connectivity. It finally struck me that the cable modem - an old Comcast Business Router/Modem is also a router (and of course the old network must have had the same problem, as the router/modem was connected to the netgear router).

My ideal solution would be for him to buy a new DOCSIS 3.0 modem, and eliminate the problem (but I am not even sure if there is a problem), although I will look into figuring out how to access the modem/router's configuration.

But if there is full connectivity, and he is getting 23down/18up for internet speeds, do I even need to worry about this? And just ignore the yellow light on the Airport?

Thoughts?

 

[John Kotches]

my suggestion, put the airport extreme into wap mode. have the existing router handle all ip address assignment.

most consumer grade gear really doesn't handle this type of network well.

I would have opted for a hi power wap rather than the airport extreme myself. the high powered wap devices give you greater coverage area and if it's a bigger facility you'll have better signal everywhere.

anyway, not trying to make you change any of the gear but you only want 1 router in the picture.

as far as changing the cable modem / router goes I would opt for the 3.0 unit for future compatibility.



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[JAG72]

If you want to try to fix the issue without having to purchase anything else see if you can put the cable modem\router in bridge mode not the airport extreme. This will allow the airport extreme to pass without the cable modem\router being in the loop.

My cable modem can not get around this so I personally just live with the dual NAT. There isn't anything that I have found that can't be done with this setup.

 

[rockymtnhigh]

If you want to try to fix the issue without having to purchase anything else see if you can put the cable modem\router in bridge mode not the airport extreme. This will allow the airport extreme to pass without the cable modem\router being in the loop.

My cable modem can not get around this so I personally just live with the dual NAT. There isn't anything that I have found that can't be done with this setup.

I am going to figure out the brand of the modem when I go back, and see how to access its settings. But since the system is working flawlessly, its pretty low on the problem list. Now I have discovered that the one "local" printer they have (which only one computer prints to) is connected by ethernet. And its an old Brother printer. the Airport network does not see it (I am pretty sure the Brother expects a 192.x network not a 10.1.x one. Of course, the online manual for it references OS 9. Yes, OS 9. My solution for this is simple. Going to get a 10 foot USB A to B cable and go direct.

 

[JAG72]

If they have the SMC8014 for their gateway you can forget about configuring bridge mode to help solve your problem. If they are using the SMCD3G then that is the DOCSIS 3.0 version and is capable of being setup in bridge mode.

From some reading if you want to get rid of the error light with the SMC8014 you would just need to configure the Airport Extreme to be in the DMZ of the gateway. This will mask the issue.

Other solution would be to do what John suggested and put the Airport into WAP mode.

 

[John Kotches]

since Rocky is the apparent support staff for the gym, I'm all for KISS. Simple, reliable and easy to maintain.




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[rockymtnhigh]

since Rocky is the apparent support staff for the gym, I'm all for KISS. Simple, reliable and easy to maintain.




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Its what I get for opening my big fat mouth about needing a better network -- their Wireless G providing "free" wi-fi just was not cutting it!

I am doing everything to keep it simple.

 

[digiblur]

Turn off the dhcp in the wireless router. Now set it to one ip above the gateway... Plug in the cable from the real router into one of the ethernet ports... Plug nothing into the wan port. 5 minute fix and call it a day.

Sent from my C64 w/Epyx FastLoad cartridge

 

[rockymtnhigh]

If they have the SMC8014 for their gateway you can forget about configuring bridge mode to help solve your problem. If they are using the SMCD3G then that is the DOCSIS 3.0 version and is capable of being setup in bridge mode.

From some reading if you want to get rid of the error light with the SMC8014 you would just need to configure the Airport Extreme to be in the DMZ of the gateway. This will mask the issue.

Other solution would be to do what John suggested and put the Airport into WAP mode.

I am pretty sure it is an old router/modem, and I think it is a SMC router. I'll check when I am there tomorrow. Masking the issue would be fine. I know bridge mode did not work.

 

[JAG72]

since Rocky is the apparent support staff for the gym, I'm all for KISS. Simple, reliable and easy to maintain.

Everything being discussed would apply to the KISS methodology. Nothing complicated with any of the solutions that have been suggested.

 

[JAG72]

I am pretty sure it is an old router/modem, and I think it is a SMC router. I'll check when I am there tomorrow. Masking the issue would be fine. I know bridge mode did not work.

Bridge mode on the SMC not the Airport. Bridge mode on the SMC pretty much disables the router functions and just passes everything over to the Airport to handle.

 

[rockymtnhigh]

Bridge mode on the SMC not the Airport. Bridge mode on the SMC pretty much disables the router functions and just passes everything over to the Airport to handle.

Once I figure out the router model, I can work on that.

 

[Foxbat]

Turn off the dhcp in the wireless router. Now set it to one ip above the gateway... Plug in the cable from the real router into one of the ethernet ports... Plug nothing into the wan port. 5 minute fix and call it a day.

If the cable modem/router is set up to NAT then that should solve the problem. Setting up the Airport Extreme for Bridge mode should achieve the same thing. Let the cable modem/router handle DHCP and the Airport just provides the Wi-Fi.

 

[navychop]

My Extreme is set up as a WAP off a Fios wireless modem/router. This is the simplest and cheapest fix, IMHO. And you don't even have to know how to run the setup on the old or even know the PW or how to reset it.

 

[rockymtnhigh]

So, I wake up this morning to a call from the gym. Network is down. I said most probably the internet is down from comcrap. Told him to pull the power on the modem and the router and give it ten seconds. I went over and still no net.

Go to the Airport utility and see no internet connection, no dns, etc.. and a 169 ip address. I pull the power on the router and restart, nothing. Then start looking at the hardware. The WAN connection from the Cable Modem was connected into a LAN port on the router. I moved it. And voila! We have net.

:shakes-head:

Apparently they started pulling all sorts of plugs when the internet did not come on this morning. Sigh... Told him if it happens pull the power from the modem and the power from the router. And leave everything else alone.

But actually I was relieved. Did not want to deal with network problems this morning.

 

[lparsons21]

If the cable modem/router is set up to NAT then that should solve the problem. Setting up the Airport Extreme for Bridge mode should achieve the same thing. Let the cable modem/router handle DHCP and the Airport just provides the Wi-Fi.

I just changed ISPs from cable to DSL. The cablemodem was not a router, so the Extreme did all the routing.

But the DSL is a wireless/wired modem/router. Put the Extreme in Bridge mode and all was good and is the simplest way to do it, imo.

 

[navychop]

...... The WAN connection from the Cable Modem was connected into a LAN port on the router. I moved it. And voila! We have net.

:shakes-head:

Apparently they started pulling all sorts of plugs when the internet did not come on this morning. Sigh... Told him if it happens pull the power from the modem and the power from the router. And leave everything else alone.

But actually I was relieved. Did not want to deal with network problems this morning.

Nice when it's simple. I believe our router at work auto senses so you could plug in anywhere. Not sure, not gonna go check, taking a few days off to go to the NY Renaissance Festival (& some tile museum & castle).