[NEBULA] NSG 50 Site-to-Site VPN Problem / Dropping Tunnel every 30 seconds

MWService Posts: 1
edited April 2021 in Nebula

Hello fellows,

We bought an NSG 50 (nearly 1 year ago i think) to replace an USG-20-VPN.

First we used it behind an LTE Modem, established multiple VPN IPSEC Site-to-Site connections we are in need of. (Mostly to other USG (60, 50) and a few to no Zyxel Devices.

Unfortunately we had to switch over to the USG 20 VPN again, because we had disconnects in the vpn tunnels. (nearly every 30 seconds). We thought it had to do with the LTE Connection.

After nearly 1 year now we had a usecase again for the NSG. We deployed it with an ISP with a dedicated line.

Unfortunately we have the same issues again. Exactly every 30 seconds it loses the VPN Tunnels and reconnects again.

This is very annoying and i dont know what we can do.

We are on latest firmware. Tested it now on multiple ISP's and with multiple Firewalls of multiple Brands on the other side of the tunnel. Same problems.

Could this device be defect from the first day on ?

Anyone else facing those issues ?

Is there any solution ?


  • Zyxel_Jason
    Zyxel_Jason Posts: 395  Zyxel Employee
    First Anniversary 10 Comments Friend Collector First Answer

    Hi @MWService,

    Welcome to Zyxel community!

    May you help to check if you have already configured a pingable IP address in Private subnet column? It is for VPN connectivity check feature(every 30 seconds).

    Since there are more users report the same symptom, we add a note in our Nebula 2.0.

    Hope it helps.


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