2 USG Flex50s, IPSec VPN with VTI and Multicast IPTV



so my goal is to be able to watch my Multicast IPTV service which I pay for from my home to another location. For this, I purchased two Zyxel USG Flex50s. There is an article on the Zyxel site which I followed to the point and I set up the IPSec VPN with VTI, it connects, I can see multicast traffic in the IGMP Statistics but the STB is not connecting.

So basically the setup is in location 1 I have an ISP router where the IPTV comes in from and it’s VLANd on ports 3 and 4. So to my USG50, I have ISP Port 1 → USG50 WAN port for internet and ISP Port 4 → USG50 Port 5 (OPT). In Location 2, ISP Port 1 → USG50 WAN port for internet and then the IPTV STB in LAN1.

Can anyone please assist on configuration?

All Replies

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

    Hi @Andr8174 Yes, USGFLEX50 supports IGMP proxy IPSec VTI tunnel.

    May I know your IGMP direction on WAN, LAN, VTI interfaces on both sides?

    And did you see the IGMP traffic on the remote side?

  • Andr8174
    Andr8174 Posts: 3
    Friend Collector First Comment
    edited September 2023

    So USGFlex50 #1: this is where the mutlicast stream comes in from the ISP router:

    WAN: Downstream
    LAN5/OPT port: Upstream
    VTI: Downstream

    USGFlex50 #2: where the STB is plugged in to LAN1 port to receive the stream

    WAN: Upstream
    LAN1: Downstream
    VTI: Upstream

    I followed the instructions in this article for the whole configuration but it does not seem to work:


    There must be some other issue with routing or am I supposed to set an IP to the LAN ports on either side? The IP On USGFlex50 #1 is set to automatic and it gets some IP address 10.x.x.x which seems kind of strange.. I assume it is getting this IP address from the multicast server from the ISP router?

  • Andr8174

    @Zyxel_James Have you seen my response? Any assistance?

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