Whole device trottle when passing traffic trough VPN


Hi all,

I'm encountering a peculiar issue with one of my devices and am having difficulty pinpointing the cause. I was hoping someone here might have some insights.

I am using a Zyxel USG FLEX 200 for a small office we have in London. It's set up with PPPoE using BT credentials, as the USG functions as both our router and firewall. Furthermore, I've configured an IPSec VPN from this London office to our main office located in another country.

With this setup, everything works seamlessly for everyone. However, there's a strange twist. Whenever I access the web interface of the London Zyxel, all users, including myself, experience a loss of 80-90% of all packets.

I've ruled out broadband issues : we've had video conferences with two individuals presenting to 15+ participants without a hiccup. The office has a bandwidth of around 20 Mbps, which suits our needs. This packet loss phenomenon also happens during times when no other users are active, and I alone attempt to access the Zyxel's web interface.

From my perspective, it seems the Zyxel device might be the root of the issue. Does anyone have thoughts or similar experiences?

All Replies

  • Zyxel_James
    Zyxel_James Posts: 626  Zyxel Employee
    First Anniversary 10 Comments Friend Collector First Answer

    @mlaur47 I would like to clarify some information first

    1. How did you determine the packet loss? did you capture packets on both WAN/LAN interfaces?
    2. Which interface did you login to cause this problem? WAN, LAN, or via VPN? If WAN, is it possible to provide remote access? you may contact me via private message.
    3. Did the event log show anything like "Zysh Daemon Busy"?
    4. You may also provide the diagnostic-info while the issue occurs via private message. Reference: https://support.zyxel.eu/hc/en-us/articles/360001516479-Firewall-Creating-A-Diagnostic-File

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