Airport Extreme / Comcast Issues

Discussion in 'Mac Accessories' started by henrysherman, Sep 2, 2012.

  1. henrysherman macrumors newbie

    Sep 2, 2012
    San Francisco
    I'm not technically inclined, so forgive any confusing statements. If you respond with questions I can certainly reply:

    Set Up
    Comcast Cable Modem
    Airport Extreme (5th generation)
    2 Airport Express base stations

    For the last 5+ months, we haven't had any problems. Setting-up the Extreme wasn't easy, but I got it to work and had the Airport Express devices working fine, connected to speakers in the house and running music through Home Sharing.

    Last week we had to reset our Comcast cable modem and now nothing works.

    Steps to Date
    1. I've reset the cable modem and powered down
    2. I've unplugged all the Airport Express base stations
    3. I've powered down the extreme, unhooked all of the cables
    4. I've also used the reset button in the back of the extreme
    5. I restarted the cable modem, waited for it to power up and reset it
    6. I spoken with comcast and they have a strong signal to the house
    7. Hooking up directly to the PC from the comcast modem works fine (that is how I'm posting now).

    Re-Set Up Steps
    Here is what I just tried, with no success
    1. Started with the entire ecosystem unplugged
    2. Reset the Comcast cable modem and let it cycle through
    3. Powered down the Comcast cable modem
    4. Once it had cycled up, plugged in the Extreme power chord to let it power up until it was flashing yellow
    5. Hooked the Ethernet cable from the cable modem to the extreme until I got a green light
    6. Tried to connect my iPad - got a full wireless signal - checked Manage the network and it is showing a green light for the Extreme and a yellow light for the Internet
    7. Plugged an Ethernet cable from the Extreme to the PC and got the 'weak/no' connectivity icon.
    8. Still have a green light on the Extreme through all this
    9. So I unplug the same cable from the back of the extreme and plug it in to the PC, power down the cable modem and internet connectivity comes back to the PC.

    Does my Extreme need to be replaced?

    Any thoughts suggestions would be greatly appreciated.
  2. Mike in Kansas macrumors 6502a

    Mike in Kansas

    Sep 2, 2008
    Metro Kansas City
    I can't tell what order you did the cable modem reset and the Airport Extreme reset, and what cables were attached at the time. I just went through a similar experience, and for some reason it took me a lot longer to set up than I thought an Apple product would. But after I finally figured it out, I've been able to repeat the steps multiple times and now only takes a couple of minutes.

    1. Unplug airport extreme ethernet cable from cable modem.
    2. Reset cable modem.
    3. Ensure cable modem works by plugging in computer directly to it (like you have done in the past).
    4. Plug ethernet cable from airport extreme to cable modem.
    5. Turn on airport extreme.
    6. Do a hard reset of the airport extreme - this means you need to hold in the reset button longer than a soft reset - about 5 seconds. The lights will flash yellow rapidly.
    7. Give it time to connect (about 45 seconds) to network.
    8. Connect to it from your PC and set up your network connection; be aware that this will have wiped out a lot of your network settings, so make sure you have them written down somewhere.
    9. Plug your computer directly into one of the network ports of the airport extreme and verify you can connect to the internet.
    10. If that all works, set up your wireless network (if you hadn't yet). You should be able to connect to your network, and your network should be able to connect to the internet.
  3. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Is the Comcast cable modem also a router/wifi station? If so, try putting your Extreme in bridge mode.
  4. henrysherman thread starter macrumors newbie

    Sep 2, 2012
    San Francisco
    This worked to get the extreme up and running. Now on to the airport express base stations. Thank you so much - I was about to go crazy.
  5. Mike in Kansas macrumors 6502a

    Mike in Kansas

    Sep 2, 2008
    Metro Kansas City
    I think the hard reset was the key for me. When I was setting it up out of the box, it didn't grab my Comcast credentials and IP addresses correctly; it took a hard reset to clear that whole thing out and go out and get them again from the modem.
  6. shortcut3d, Sep 6, 2012
    Last edited: Sep 6, 2012

    shortcut3d macrumors 65816

    Aug 24, 2011
    Comcast supports IPv6 on some modems. This may cause Internet connectivity issues immediately after restarting because Airport Extremes support IPv6 pass through. Certain websites may not resolve using IPv6. Check your cable modem for IPv6 support. The default IPv6 settings for the Airport Extreme should not be changed. IPv6 pass through is enabled by default.

    Restart the cable modem without the Airport Extreme Ethernet WAN port connected.

    Wait for downlink and uplink confirmation (steady lights) and Internet symbol (blinking light).

    Restart the Airport Extreme. Then connect the Airport Extreme Ethernet WAN port to the cable modem once the solid green light indicates the device is ready.

    3TB Time Capsule 4th Generation
    Airport Extreme 5th Generation
    Motorola SB6141
    Comcast Xfinity Xtreme 105

    NOTE: Comcast will periodically send firmware updates (profiles) to the cable modem, which force a restart. Since the Airport Extreme is likely connected during the restart the Internet becomes temporarily unavailable. The cable modem is not renewing the host on the network and the Airport is not getting a refreshed WAN. To force the refresh, you must follow the restart sequence in the proper order above. This issue is less likely to occur with IPv4 only.
  7. jolubo macrumors newbie

    Oct 9, 2012
    Airport / Comcast reset: solutions?

    Summary: had to have Comcast technician out

    After a few years of stability, it seemed I'd have to reset the Comcast modem daily, by unplugging it for 15" to get the internet to work without interruption. I switched out modems at Comcast's suggestion, thought it worked, but problem reappeared. Since the Airport Extreme was warm, I bypassed it, still had problem. Comcast thought I had a strong signal.

    Realized problem started after college kid came home with MacBook, iPod, iPhone, all on same wireless Airport Extreme network that runs iMac, iBook, iPod, Roku, Nook and iPad. Changed over several devices to Guest network, seemed to fix it!....for about a week.

    Finally had Comcast technician come out. Our cable from the street was under strain, evidently. Also found that signal weakened through splitters from street to back of house.

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