Airport Not Seen in Utility But Connection Works

[MJedi]

Hello,

We recently moved and transferred our Comcast service. In the process, Comcast "upgraded" me to their Wireless Gateway. But I preferred to keep using my Airport Extreme Base Station AC router. So I set the Comcast Gateway to Bridge Mode following their instructions. The weird thing is that now my Airport Extreme is not seen by Airport Utility, whether I'm connected to it wired or wireless, from any device (Mac, iPhone.) But the network works: I can browse the Internet; I can connect to the shared drive attached to the Airport. The light is green on the router. Before the move, Airport Utility could see the Airport Extreme. Is it because the new Comcast router has an IP address of 10.0.0.1? I've already rebooted the Comcast router and Airport Extreme several times. Any other suggestions? Thanks.

 

[techwarrior]

So, the Comcast device is a modem\router combo, right? So, it is directly connected to the coax cable. Unless you have a separate modem, the Comcast router must be configured as the primary router, but you can add the AP Extreme in bridged mode.

AP Utility uses a non-routable network discovery protocol to find the Airport devices. As long as they are on the same subnet, then they should be visible. If the AP Extreme was in router mode, it would get IP on the WAN interface from Comcast, then create a different network for internal connections. In this case, you would only see the AP if you connected to it directly either by Wi-Fi or Ethernet.

 

[belvdr]

Hello,

We recently moved and transferred our Comcast service. In the process, Comcast "upgraded" me to their Wireless Gateway. But I preferred to keep using my Airport Extreme Base Station AC router. So I set the Comcast Gateway to Bridge Mode following their instructions. The weird thing is that now my Airport Extreme is not seen by Airport Utility, whether I'm connected to it wired or wireless, from any device (Mac, iPhone.) But the network works: I can browse the Internet; I can connect to the shared drive attached to the Airport. The light is green on the router. Before the move, Airport Utility could see the Airport Extreme. Is it because the new Comcast router has an IP address of 10.0.0.1? I've already rebooted the Comcast router and Airport Extreme several times. Any other suggestions? Thanks.

What if you disconnect the WAN from the AE and wire into the back of the AE directly? Are you able to see it then?

 

[MJedi]

So, the Comcast device is a modem\router combo, right? So, it is directly connected to the coax cable. Unless you have a separate modem, the Comcast router must be configured as the primary router, but you can add the AP Extreme in bridged mode.

AP Utility uses a non-routable network discovery protocol to find the Airport devices. As long as they are on the same subnet, then they should be visible. If the AP Extreme was in router mode, it would get IP on the WAN interface from Comcast, then create a different network for internal connections. In this case, you would only see the AP if you connected to it directly either by Wi-Fi or Ethernet.

I think I understand what you mean. However, I would rather not use the Comcast device as the router. Who knows what security issues it has, and how often they update the firmware? I've already set the Comcast device in Bridge Mode, which supposedly turns it into a plain cable modem. The Comcast device has a local IP address of 10.0.0.1 (which is the address of its built-in web management tool) and my local network uses the 192.168.1.x address range. Is that difference causing the problem with Airport Utility?

What if you disconnect the WAN from the AE and wire into the back of the AE directly? Are you able to see it then?

Yes, Airport Utility sees it but only after I reboot the router with the WAN cable disconnected from the Comcast device. And when I plug the cable back, without rebooting anything, Airport Utility cannot see it again.

 

[techwarrior]

The Comcast device has a local IP address of 10.0.0.1 (which is the address of its built-in web management tool) and my local network uses the 192.168.1.x address range. Is that difference causing the problem with Airport Utility?

Which Comcast device do you have? It might help to know the model, the documentation or Comcast forums might lend more insight into the proper configuration of the device in bridge mode?

How are you connecting? Hardwired to the Comcast or AP? Or Wi-Fi? What is your IP Address when you launch AP Utility and can't see the Extreme?

I wouldn't be so worried about the security of the Comcast device, they generally use decent gear and keep up with FW Updates.

 

[belvdr]

I think I understand what you mean. However, I would rather not use the Comcast device as the router. Who knows what security issues it has, and how often they update the firmware? I've already set the Comcast device in Bridge Mode, which supposedly turns it into a plain cable modem. The Comcast device has a local IP address of 10.0.0.1 (which is the address of its built-in web management tool) and my local network uses the 192.168.1.x address range. Is that difference causing the problem with Airport Utility?

Yes, Airport Utility sees it but only after I reboot the router with the WAN cable disconnected from the Comcast device. And when I plug the cable back, without rebooting anything, Airport Utility cannot see it again.

So, when you place the Comcast device into bridge mode, it shouldn't have any IP addresses on it and should not be offering any services, such as DHCP. My guess is that it is not truly going into bridge mode.

I second @techwarrior's suggestion in that knowing the device model and manufacturer can help.

 

[MJedi]

Which Comcast device do you have? It might help to know the model, the documentation or Comcast forums might lend more insight into the proper configuration of the device in bridge mode?

How are you connecting? Hardwired to the Comcast or AP? Or Wi-Fi? What is your IP Address when you launch AP Utility and can't see the Extreme?

I wouldn't be so worried about the security of the Comcast device, they generally use decent gear and keep up with FW Updates.

I have their Wireless Gateway XB3, which is a Cisco DPC3941T. I can be wired or wireless to the Airport Extreme. My IP address is in the 192.168.1.x range.

So, when you place the Comcast device into bridge mode, it shouldn't have any IP addresses on it and should not be offering any services, such as DHCP. My guess is that it is not truly going into bridge mode.

I second @techwarrior's suggestion in that knowing the device model and manufacturer can help.

I'm almost sure it's not offering DHCP because the Airport light is green. When I initially set this up, and the XB3 was acting as a router, the Airport light was blinking yellow, and the Airport Utility complained of Double NAT.

So either I change my network from 192.168.1.x to 10.0.0.x, or find a way to change the modem's IP address.

 

[belvdr]

Great troubleshooting! With everything configured as you want, disconnect the WAN port of the AE. Launch Airport Utility and login. Now connect the WAN port to the AE.

Do you get disconnected? If not, are you able to see the WAN IP of the AE? I'm curious if you're getting a public or private IP.

Things like this frustrate me with Apple's Airport devices. I much prefer a standard web browser or, even better, a console port.

 

[techwarrior]

I have their Wireless Gateway XB3, which is a Cisco DPC3941T. I can be wired or wireless to the Airport Extreme. My IP address is in the 192.168.1.x range.

Thanks for the additional info. So, the only useful info I found was a Comcast Forum article that suggests the only LAN port that is enabled when Bridge Mode is activated is LAN1. But, since you can reach the Internet while connected to Airport, then this is not the issue. It also suggests the modem is still accessible via http://10.0.0.1/ which implies the modem is still responsible for doing NAT, it should be getting a 7x.xx.xx.xx address from the Comcast network, and assigning an internal 10.0.0.1 address to the LAN port. So, the AP must be getting a 10.0.0.2 address for WAN and then assigning 192.x.x.x addresses using DHCP for internal LAN connections.

It still doesn't make sense that the Utility is not seeing the Extreme. As @belvdr suggested, try connecting to the Extreme with AP Utility when the WAN port is disconnected. Now the next thing is just a wild stab, but on the Base Station tab, do you have your Back to My Mac enabled? If so, try removing that, press Update, and wait for the Extreme to recycle. Then, while connected with AP Utility, connect the WAN port. The thinking here is in a recent update, Apple fixed something that caused AP devices to disappear from the Utility when BTMM was enabled (I had this issue on my Time Capsule). I am guessing that maybe there is a tie in between BTMM and that it is not accessible through the WAN port in this setup as the Modem is effectively putting the Extreme in a DMZ and still doing some routing functions which block BTMM? It would be interesting to know if the WAN IP Address on the Extreme is 10.0.0.x when you connect the WAN port (assuming you can remain connected to the device via AP Utility).

It may be that Cisco, being the self-designated router king of the world, is not truly disabling all routing functions in Bridge Mode and that is blocking Utility access to the device.

Comcast supports 3rd party modems that you can pick up at most Electronics resellers. I use a Surfboard 6120 which is a DOCSIS 3.0 modem, the nice thing is that owning your own modem gets you around the $10 monthly rental fee for the provided router (you do have to return it to them to get the credit). You will have to register the modem, https://www.xfinity.com/support/internet/activate-purchased-modem/ but it is a sure way of getting to your desired state and saving $120 a year for a device that is not even being used for it's full capabilities.

 

[MJedi]

Thanks for all your suggestions. I ended up resetting the Airport to defaults, and configuring it from scratch. It is staying visible in Airport Utility now.

I then re-introduced a second Airport Extreme AC which extends my network. It had been working before the move. It was not visible, but devices wired to it works. I was about to reset it, when I thought I should update its firmware. I had both Airports at 7.7.7. Turns out one of the issues that 7.7.8 fixes is Airports not being seen by Airport Utility when Back to My Mac is enabled. So, after I updated the second Airport to 7.7.8, it's now visible even with BTMM enabled. I guess I should've updated in the first place. In my defense, I've not had this problem until after the new modem, so I didn't think it was an issue. I didn't enable BTMM in the first Airport after I reset it.

So, all is working now. Thanks again @techwarrior and @belvdr!