No dhcp handout on 2.4GHz

Discussion in 'ASUS AC Routers & Adapters' started by j_s, Nov 29, 2012.

  1. j_s

    j_s New Around Here

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    RT-AC66U running fw 3.0.0.4.246.20 (Merlin), strange behaviour:

    My wired clients get ip-addresses and also one laptop on wifi 5GHz.

    But all clients on 2.4GHz cannot get an ip-address. They seems to connect correctly (using WPA2-personal) and I have checked that they have the correct key. But they don't get an ip from dhcp.

    There is no entries in the General log when they try to connect (no DHCPREQUEST etc), but when I look in Tools|Sysinfo it lists 2 Wireless clients on 2.4GHz (Associated 2 - Authorized 2 - Authenticated 2).

    I have tried to restart the router and the devices but to no avail.
     
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  3. RMerlin

    RMerlin Part of the Furniture

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    Double check to make sure the wireless interface of those computers are set to "Automatic IP" and not to some static IP.

    If running Windows, open a command prompt and check what IP they are using on the wireless interface (if any), by running this command:

    Also make sure you don't have another DHCP server running on your network (for instance on an access point, or a VoIP gateway). The "ipconfig" command should tell you what default gateway is being handed to them (if they do get a DHCP lease from somebody else), which would typically be the IP of the device handing out the lease.

    You can also get more detailed info with "ipconfig /all", including the DHCP server handing out the lease.

    On the wifi end of things, make sure you are on AES and not TKIP since you are using WPA2.
     
  4. j_s

    j_s New Around Here

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    Checked that the devices are on automatic, no other DHCP server on the network that I know of.

    My table-top internet radio says "connecting" and "negotiating ip" and when I check it has ip 169.254.237.237 (my network is 192.168.0.*).

    My laptop pc running windows 7 - typed ipconfig and it reports that all network interfaces are disconnected.

    In the router gui: Wireless - General tab - WPA Encryption combo there is only "AES" - I can not choose anything else.
     
  5. RMerlin

    RMerlin Part of the Furniture

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    Try setting your router on channel 1 and see if it works. That could happen if your router is on a channel not supported by your wireless interfaces (for instance channel 13).

    Also make sure you didn't accidentally enable the Wireless MAC Filter on the 2.4 GHz band.
     
  6. j_s

    j_s New Around Here

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    The router aready is on channel 1. MAC filter mode says "disabled".

    The problems started a couple of days ago when I first noticed that the internet radio would not connect in the morning, then the same thing with the laptop computer. Strange that my other laptop which has a 5GHz network card does not have these problems.

    Before that it has been fine the whole time since I installed the router back in July.

    Can I do some kind of factory reset on the router?
     
  7. RMerlin

    RMerlin Part of the Furniture

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    It's worth trying. Either click on the option to restore to factory defaults on the webui, or use the WPS button trick (turn the router on while WPS is being pressed, wait a few secs, then release the WPS button).

    Don't restore a saved settings file however, or it would just restore whatever corrupted/invalid setting you had.
     
  8. j_s

    j_s New Around Here

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    Well, I don't know what to make of this, but the router works now.

    I did a factory reset using the following procedure:
    • Disconnected the cable to the adsl-modem from the router so as not cause problem with conflicting ip-addresses.
    • Pressed wps-button for 30 secs, power off, continued pressing wps-button for another 30 secs, power on, continued pressing wps for 30 secs.
    • Logged on to the router using the default 192.168.1.1.
    • Downloaded firmware 3.0.0.4.220.18b (Merlin build) and flashed it.
    • Re-entered my own settings - router ip 192.168.0.1 and dhcp range 192.168.0.100-199. [The reason for using 192.168.0.1 is that my Linksys AM200 adsl modem is on 192.168.1.1 in bridge mode.]
    • Reconnected the modem.

    Everything worked perfectly - no problems for the 2.4GHz devices connecting and getting ip-addresses.

    I the downloaded firmware 3.0.0.4.246.20 (which I had used previously) and flashed it.

    My problem re-appeared in that no 2.4GHz devices could get an ip. My 5GHz laptop also had problem connecting.

    Re-flashed 3.0.0.4.220.18b and now everything is OK.
     
  9. j_s

    j_s New Around Here

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    Just to clarify:

    1. I downloaded a fresh copy of 3.0.0.4.220.18b before I initiated the reset to factory defaults.
    2. I also downloaded a fresh copy of 3.0.0.4.246.20.

    Both downloaded from Merlin's website:
    http://www.lostrealm.ca/tower/node/79
     
  10. RMerlin

    RMerlin Part of the Furniture

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    I have no other idea as to what could be causing such an issue, as I have had no other report of it in the couple of thousands of users running it, sorry. The wireless driver is exactly the same in build 220.18 and 246.20.
     
  11. j_s

    j_s New Around Here

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    Thanks for your efforts, Merlin. I'll stay on 220.18 for the time being, not a big issue really.
     
  12. dusthead

    dusthead New Around Here

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    make me #2. Started out with the "wtf? corrupted firmware on an out of the box device!?" haha, as many have. this forum got me through that, so now i'm running the stock 3.0.0.4.260. seemed to work fine until i turned off my 5Ghz antennae. Nothing I own has an 802.11n NIC in it, so i figured i didn't need both on. Going to try turning it back on to see how it goes tonight - but thought i'd let you know he's not the only one.

    It's odd though because multiple issues began once I did this:
    1 - HP laptop would authenticate/connect to the network but wouldn't be served a DHCP address (it would use APIPA), but if i give it an IP address of my own that i know is correct for the network - it works.

    2 - the android phones connected to the router will lose connection to the internet but look like they're well connected to wifi...up arrows will show up and blink but no down arrows and no connection to the net via wifi. UNTIL I power cycle the wifi on my phone...then it's random how long it will last...typically won't die on me while using it, only after idle time.

    all wired connections...only one...work perfectly fine 24/7.
     
  13. wvaj

    wvaj Occasional Visitor

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    Channel Bandwidth

    Next time you guys run into this issue try turning the 2.4GHz bandwidth to 20MHz only. This was happening with my Windows phone almost all the time. It would connect sometimes, and not connect as soon as two minutes later!

    Goto:
    Advanced Settings - Wireless
    Frequency (2.4)
    Look for channel bandwidth and set it to 20MHz.

    I haven't had an issue since. Both my tablet & desktops run off the 5GHz, so the bandwidth on the 2.4 band really didn't matter to me.
     

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