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DHCP Request loop takes down my internet

Discussion in 'Asuswrt-Merlin' started by Gitsum, Mar 19, 2019.

  1. Gitsum

    Gitsum Senior Member

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    Here's an odd thing that started to happen recently, whenever I turn on my VPN client software on one of my computers and start flowing some traffic for 10-20 minutes, I lose my internet connection. When I call tech support to fix it, they have to reboot the media converter outside my house, (fiber optic to CAT5) and tell me that they're equipment is stuck in a DHCP loop trying to give my router an IP address even though I have a static IP. I don't get it.
    I'm using an ASUS AX88U with Merlin firmware.
    The technician said it happens to other customers besides me but it doesn't make sense to me.
     
  2. Gitsum

    Gitsum Senior Member

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    So, Merlin, if you could take a look at this, what I've narrowed down with my ISP as to what is happening is that my ASUS AX88U with Merlin 384.10 beta2 5640 is requesting an IP address through DHCP even though I have a static IP set up with them. So the ISP DHCP server keeps denying the request and the router asks again and on and on it goes till my connection just quits working.
    This only happens though when I am running a VPN client on one of my computers after 10-20 minutes. This only started happening once I started using the 384.10 series of firmwares.
    Going to go back to 384.9 and see if that fixes it.
    Thanks.
     
  3. RMerlin

    RMerlin Super Moderator

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    Works properly for me, the dhclient program is no longer running on the router while in static mode.. Check to make sure you don't have something else sending DHCP queries through your connection to your ISP.
     
    Vexira likes this.
  4. Gitsum

    Gitsum Senior Member

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    I'm not even sure how I could figure that out. They said the DHCP requests were coming from the MAC address of the ASUS router.
    I do have about 18 devices on my network, but one of them would have to know the gateway IP of my ISP, wouldn't it?
     
  5. RMerlin

    RMerlin Super Moderator

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    I'm not sure either how DHCP queries could end up being sent to your ISP. If the issue happens when using a VPN tunnel, then maybe it's comehow coming from that tunnel.
     
    Vexira likes this.
  6. Gitsum

    Gitsum Senior Member

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    So, I've switched to a Netgear router and the problem has disappeared.
    Is it possible the ASUS router has some kind of an issue with the media converter box outside my house where the fiber is converted to a CAT5 that connects to the router??
    I think the problem may have started when you made changes to strongswan or something like that?
    Doesn't that have something to do with the WAN port on the router?
     
  7. RMerlin

    RMerlin Super Moderator

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    Strongswan has nothing to do with WAN, it's the IPSEC server.
     
    Vexira likes this.
  8. Gitsum

    Gitsum Senior Member

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    Ok, well that still doesn't explain the problem. I've noticed some other people reporting WAN disconnects, just like what mine does. I will try using stock ASUS firmware and see what happens.
     
  9. L&LD

    L&LD Part of the Furniture

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    The fact that switching out a router works for you indicates that the Asus router wasn't properly setup?

    Has a reset to factory defaults been performed on it after flashing the firmware you are now using? Did you minimally and manually configure the router to secure it and connect to your ISP?

    What features or other options have you enabled/disabled that are not defaults? Or, do you run any additional scripts or other customizations on it?

    If the router is not in a good/known state, then your troubleshooting will greatly increase in difficulty, time and frustration.

    https://www.snbforums.com/threads/faq-nvram-and-factory-default-reset.22822/

    If any of this seems applicable to you, then I recommend the M&M Config procedure to get your router working as you need.

    Please see the links below in my signature for further details on how to complete the steps required to get to a good/known state.
     
  10. Gitsum

    Gitsum Senior Member

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    Tried it again this morning with latest ASUS firmware and full reset of factory defaults and manual config. It ran for about 3 hours with my VPN client running on a PC and went down.
    Very odd scenario.
     
    L&LD likes this.
  11. L&LD

    L&LD Part of the Furniture

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    Very odd!

    Are there any obvious settings you can copy from the Netgear router to match on the Asus router? The Asus defaults need some tweaking, but which ones?

    Anyone else has any insight?
     
  12. Gitsum

    Gitsum Senior Member

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    Well, I was able to get the WAN to go down with the NETGEAR also.... this is frustrating. I think my ISP is doing something if I am uploading too much or something. Thanks.
     
  13. L&LD

    L&LD Part of the Furniture

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    'Too much' meaning total MB's, or how fast it is uploaded?