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Your ISP's DHCP does not function correctly

Discussion in 'ASUS Wireless' started by johndoe0511, Jan 5, 2018.

  1. johndoe0511

    johndoe0511 New Around Here

    Jan 5, 2018
    I have an Asus RT-AC66u that shows this message any time my ISP (Charter in Georgia) drops the connection, which has now become every few days. My only recourse is to power cycle the cable modem. I've had Charter out to check the line and modem and they say everything checks out.

    In researching this, I've come to find out this seems to be an Asus thing. I use the Merlin firmware, and this has happened with multiple versions. It also happens with the Asus firmware. I've seen some suggest that changing the DHCP query frequency from aggressive to normal fixed the issue for them, but mine was already set on normal. My parents have an RT-AC68u, also on Charter (but in a different state) and they have no issues whatsoever. For that matter, mine used to work. But then this started happening suddenly and it's never worked normally again.

    Is there anything else I can check or do? I hate to buy another router, but having my Internet routinely go out on my security cameras isn't an option. Regarding new routers, are there ones I should look into? Is this really mostly just an Asus issue? I don't want to spend $200+ only to have the same thing occur.

  2. outlaw78

    outlaw78 Occasional Visitor

    Jan 1, 2018
    I have had the same thing happen to me on charter. Mine happens when I use "Mac Clone" under WAN. Are you using Mac clone?
  3. MFM000

    MFM000 New Around Here

    Oct 20, 2014
    Happens to me with Cox.
    Most of the time going to WAN->Internet Connection and invoking the "Quick Internet Setup" button in the upper LH corner
    and allowing it to time out works (will hang for a while then reset).

    Unplugging cable modem for 10 min usually solves the remaining ones.
    (Somehow you need to get the cable co to "forget and start over".
  4. Joboo7777

    Joboo7777 Occasional Visitor

    Jul 22, 2017
    Happened to me when I moved from 380 to 382. Not sure the resolution as I did a few things during the issue. I think it most likely was resolved by waiting a while to re-connect to the network. Interested to see if this will happen again when I upgrade to 384 as I plan to reset back to factory when upgrading.
  5. tck81

    tck81 New Around Here

    Jan 5, 2018
    I had this problem when upgrading from 380.68_4 to 380.69 on 2 different 68u's. I did a factory reset and set both of them up from scratch and they connect pretty much instantly and I've yet to get this message.
  6. Stephen Becker

    Stephen Becker Occasional Visitor

    Apr 13, 2016
    I have seen the same thing. My modem takes a very long time to boot, so I assume the problem is that the router starts up before the modem is ready. It appears like uhdcpc does not retry getting an IP address if it fails the first time (not sure why, I verified the -n flag is not set, which would explain that functionality). Most DHCP clients will send a broadcast looking for an IP address every 5 minutes if it doesn't have a lease. I have left mine running all night and it does not fix itself. Opening the WAN page and pressing Apply seems to fix the problem, which proves it is just a DHCP client problem on the router.

    I wrote this script today (so haven't fully tested it), but it pings Google's DNS every 5 minutes, if any fail, it will ping 10 times (2 seconds between each) and if all fail will release/renew your WAN interface, if any of the pings reply, it goes to sleep for 5 more minutes and loops. You could make this your wan-start script...I am not sure if it is safe to have that be a never ending script. What I did was name this script net-test and then put the follwing in my wan-start script nohup /jffs/scripts/net-test >/dev/null &



    while true;
    sleep $pausetime

    while ! ping -c1 $intadr
    if [ $i -lt 1 ]
    logger "Failed test to $intadr, Renewing DHCP..."
    killall -SIGUSR2 udhcpc
    sleep 2
    killall -SIGUSR1 udhcpc
    break 1
    sleep 2
    Last edited: Jan 14, 2018

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