[RT-AC66U 3.0.0.4.374.726] problem with ISP

[GloryEE]

Hi ALL
I have RT-AC66U with Firmware Version 3.0.0.4.374.726 and ADSL modem.
If I configure RT-AC66U to use Dynamic IP from ISP than router goes in permanent reboot. It looks like
- router started
- wifi started (i can access to router console)
- negotiation with ISP happened (i see by activity in ADSL modem)
- IP is assigned (i see it in router log)
- after few seconds all lights on router are splashed and cycle repeats.
It continues until i switch off ADSL modem. With switched off ADSL router starts and works normally. If than switch ADSL again on than reboot starts.
But if i configure router to use Static IP (same which i saw in log ) than all is Ok - no any reboots, intranet works, Internet also works.
There is also no any problems when i use USB modem in Dual WAN even with Dynamic IP. Laptop connected directly to ADSL by cable works properly and see Internet.
Router hard reset and clear configuration with default settings dont change anything.
There is also no any additional devices like USB disks connected to router.

Can you give me some advise or vision where the problem can be ?

 

[Igb]

Don't think it will be your problem, but just in case, check if "DHCP query frequency" option, under WAN, is set to "normal mode". Some ISP's don't like the "aggresive mode" setting

 

[GloryEE]

Don't think it will be your problem, but just in case, check if "DHCP query frequency" option, under WAN, is set to "normal mode". Some ISP's don't like the "aggressive mode" setting

Thank you for answer.
Both "DHCP query frequency" were tried - results are the same.
But it is not logical for me that router restarts if ISP rejects its requests.
It looks like vulnerability when my hardware can be so easy rebooted from outside.

New info, that even with static IP router reboots about once per day(maybe two). I can say exactly when, because it happens when i am out of house. I see this by Up-time in System log. I am not sure, but i suspect that reboot happens when expired IP leasing

Can it be the firmware bug, maybe some kind of overflow ?
Or can it be hardware defect and covered by warranty ?

 

[GloryEE]

If stay router in "rebooting" mode that the time between reboots grows from 1 minute till 10 minutes during next 2-3 hours.
After 2-3 hours router(?) "decides" - enough reboots and starts work properly.
But not forever. Only for next 24-48 hours.

WTF ?!