Dual Wan Failover causes DNS failure and loss of Internet

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EdC
EdC Posts: 13 image  Freshman Member
First Comment Third Anniversary
in USG FLEX H Series

For cost reasons, I moved from a dedicated Mediacom line with Public Static IP to a 'Residential' line that is DHCP internally as well as Public DHCP externally. My Static IP WAN2 has not changed. My previous WAN Trunk was weighted round robin and worked fine.

I reconfigured the WAN interface to DHCP and it picks up an address from the modem just fine. Modem sees it connected. All that works fine.

I configured the new WAN Truck as recommended with Spillover/Outbound and made WAN2 (now a specific Primary) Active, and WAN1 Passive.

During the modifications, I kept WAN1 inactive and WAN2 active. In this configuration everything works as normal. Websites both wired and via APs resolve just fine.

However, when I bring WAN1 active (even though it should not be used at all) everything stops relative to going out to the internet. I get nothing but DNS probe and DNS timeout messages and websites will not load. As soon as I put WAN1 back inactive, everything starts up again working just fine.

I am at a loss and could use any suggestions or recommendations.

Thanks,

-ed

All Replies

  • EdC
    EdC Posts: 13 image  Freshman Member
    First Comment Third Anniversary

    Another interesting tidbit. I have 3 SSIDs, two are VLAN 52, 53 and they seem to work just fine regardless of the above issue. The other is on the same 'main' network as are all the wired devices (such as my laptop) and they are all impacted the same way. Just now, the network failed for just the wired network on the main network and the one SSID. Even though WAN1 was inactive. I turned it active and then inactive and all is back working. There is got to be some sort of DNS vs. VLAN issue I am guessing… not sure what is going on

  • Zyxel_Melen
    Zyxel_Melen Posts: 4,616 image  Zyxel Employee
    Zyxel Certified Network Engineer Level 1 - Switch Zyxel Certified Network Administrator - Switch Zyxel Certified Network Administrator - Nebula Zyxel Certified Sales Associate

    Hi @EdC

    I did a quick local test for the Spillover/Outbound with same WAN setup, and everything works.

    Please help to check:

    1. What's your Global Zone Forwarder setting?
    2. Could you help to nslookup a few domains to check the dns resolution? Please use nslookup <domain> 8.8.8.8, this allows you to use the public DNS server to cross-check.
    3. If possible, please share your config file with me by sending a private message. Click my name to access my profile page and you can see a message button.
    Zyxel Melen


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