LTE5398-M904 ipv6 passthrough


Activating ip passthrough gives the expected results for ipv4 (ip from the "home" screen is allocated to the designed mac address). However for ipv6 it's different. Whatever I do the ipv6 seen from "home" screen doesn't match the one allocated to the designed mac address. Any idea?

Another question: regarding wireless clients how the routing is done? They don't have internet access anymore. Do I need an external dhcp/nat server acting also as the internet gateway?


Accepted Solution

  • Bob_C
    Bob_C Posts: 127
    5 Answers First Comment Friend Collector Fourth Anniversary
     Zyxel Employee
    Answer ✓
    Hi Christophe, 

    In terms of WiFi clients being unable to access Internet, you mention that "IP passthrough is activated", which is the key. 

    When IP passthrough is activated, only 1 end device from LAN will receive the IP address leased by the Internet Service Provider, either the first connected (IP passthrough in dynamic mode) or the MAC address-specified (IP passthrough in fixed mode). The rest of end devices will not be able to access the Internet. 

    For a use case where there are both wired and wireless end devices, I would suggest to use router mode so that both wired and wireless end devices have Internet access. However, if your use case have an HTTP(S) server, FTP server, or VPN client that requires a public IPv4 address, I would suggest to still use routing mode but set port forwrding rules for the HTTP(S) server, FTP server or VPN client.

    IP passthrough is more commonly used in a fixed wireless access scenario, where there is an outdoor LTE/NR router and an indoor router. The outdoor LTE/NR router activates IP passthrough and forwards the IP address to the indoor router, any wired or wireless clients connect to the indoor router. 

    PC ------ Indoor (public IPv4 address) - Outdoor (IP passthrough) ))) LTE ((( Mobile Network 
    Phone ))((



All Replies

  • Bob_C
    Bob_C Posts: 127
    5 Answers First Comment Friend Collector Fourth Anniversary
     Zyxel Employee

    (1) IP passthrough only happens for IPv4, meaning the IPv4 address that the LTE5398-M904 acquires from the Internet Service Provider will be leased to the connected device, e.g., a PC. In terms of IPv6, based on the default settings, the LTE5398-M904 will only lease the IPv6 prefix to the connected device, and the connected device will form its IPv6 address given the prefix. It's the design.

    (2) Can you please explain "they don't have internet access anymore" with more details?
    - Does it mean wireless clients have Internet access when they just connect but lose Internet access after a while? if so, how long?
    - In the meantime, does LAN client have Internet access?
    - Can the wireless clients open the LTE5398-M904's UI when they do not have Internet access?



  • Thanks Bob.

    (1) IPv6: make sense, that's clear now :-)

    (2) Zyxel wireless clients:
    - no internet connectivity at all (as soon as I activate IP passthrough)
    - IPv4 allocated by Zyxel router DHCP pool
    - can ping Zyxel router / open Zyxel GUI
    - no IPv6 address allocated

    (3) Zyxel lan clients (reminder 1st port is used for passthrough, client is connected to the 2nd port)
    - internet connectivity due to an IPv6 address allocated
    - no DHCP IPv4 address allocated / can't open Zyxel GUI
    - setting an static IPv4 address is useless: still can't ping the Zyxel router

    I'm lost. My idea is the following: have port 2 clients/wireless clients in the same subnet - without direct internet access - internet access being granted by a gateway/firewall connected to port 1 (with IP passthrough). Maybe I "just" need to add some routes in the GUI ... don't know.

    Thanks for your time, regards,


  • Hi Bob,

    Thanks a lot for the detailed explanations.

    I'm trying to cope with the lack of QOS parameters (wireless/lan). IP passthrough could have been a way by forwarding all the wireless traffic to another equipment apply QOS and send it back to the Zyxel router...

    There are some very basic QOS functions available at Zysh level. GUI is missing those although documentation is describing them ??

    Have a nice day, regards,


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