Bridge Mode - No IP & DNS

Question

Bridge Mode - No IP & DNS

Hey guys,

I recently underwent some big-time renovation at my home... and in the process, decided to hardwire every room with gigabit internet (hoping to be future safe). But with so many wireless devices amongst my family members, the need for a WiFi network was kinda necessary, and so, settled in for an Airport Extreme (5th gen) WiFi Router.

My setup is something like this...

I have a cable modem that first sends the internet signal to a 4-port Cisco Gigabit (wired) router. Off those 4 ports, 1 goes to a VoIP ATA, 1 to a Trendnet 8-port gigabit switch (which serves/feeds the RJ-45 outlets in my rooms), the 3rd to my Airport Extreme & the last one to another wall RJ-45 outlet.

Everything was working fine... and this setup has been in operation for a good 5 months now.

We had some issue with the RJ-45 port that was serving a line to the Airport Extreme and got that replaced 2 weeks back. Ever since, the Airport Extreme just refuses to work as expected.

The problem: As I am using a Cisco Router before the Airport Extreme, I need to use the Airport Extreme in Bridge Mode (to avoid the double NAT issues). But when I do so, the amber light blinks; and upon opening the Airport Utility, it says 'No Internet Connection' and 'No DNS'. I tried doing a soft and a hard reset, but in vain. The funny part is... if I connect my laptop directly to that port that serves the Airport Extreme... it gets the net just fine!

When I hard reset the Airport Extreme and began configuring it again... by default, it is not in Bridge Mode - and is in the mood to distribute IP addresses. It sees my Cisco Router and even gets an IP address assigned (via DHCP) from my Cisco Router. But when I change it to Bridge Mode, it goes all wanky. It refuses to get an IP from my Cisco Router and adorns a self-assigned '169.xxx...' one.

Thankfully, my entire house is hard wired... and am not crippled form accessing the net. But I need to get this WiFi up and running ASAP.

Help appreciated.

-Ambrish

PS: My Cisco Router is set to (assign addresses via) DHCP. And all the RJ-45 ports in my home are getting connectivity just fine. INCLUDING the RJ-45 port that feeds the Airport Extreme.

Posted on Apr 9, 2012 10:41 PM

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Answer 1

Tesserax

Level 10

159,412 points

Apr 9, 2012 11:08 PM in response to Ambrish L. Acharya

FWIW, I basically have the exact same setup with a Cisco RVS4000 as my main Internet router. All Ethernet connection coming from the Cisco go into a network patch panel, which in turn, provides Ethernet througout the house. I then connected an AirPort Extreme and a Time Capsule (configured as bridges) to provide wireless on both floors of my home. Neither have ever exhibited the problem you are seeing in this configuration.

The key for Gigabit Ethernet is that all four pairs of wires (inside the Ethernet cable) are used. If the cable is not terminated properly or if you have any of the runs as "dual-purpose" to support both data and phone service, you may not get full Gigabit service over that connection.

Note, when in bridge mode ALL of the Ethernet ports on the AirPort are exactly that, Ethernet ports. However, for consistency I would recommend that you connect the Ethernet run coming from the Cisco to its WAN (circle-of-dots) port.

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Answer 2

Apr 9, 2012 11:17 PM in response to Tesserax

Thanks for replying Tesserax.

My internal internet network (intranet) is separate form my house phone network. The only exception being the connectivity of my VoIP ATA. But still, no physical phones connected to this.

The ethernet cable is connected to the WAN port on my Airport Extreme. Nothing is connected to the LAN ports.

Again, I know the port feeding the Airport is working... as I connect my laptop there and it works fine. So I am guessing that the wiring is also all right.

I am really reluctant to accept that the Airport Extreme itself has somehow physically failed and is now crippled.

:-(

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Answer 3

Bob Timmons

Level 10

189,156 points

Apr 10, 2012 6:24 AM in response to Ambrish L. Acharya

Since all of the ports behave the same when the AirPort Extreme is configured in Bridge Mode.....what happens if you connect to one of the LAN ports......not the WAN port?

You can connect to any of the LAN ports and/or test any or all of them.

If this works.....you have a bad WAN port....but fortunately there is a workaround since the AirPort is in Bridge Mode.

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