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  1. #1

    TL MR3420 port forwarding and USB dongle

    Model :

    Hardware Version :

    Firmware Version :

    ISP : [/COLOR]

    I am using a TL MR3420 router with a 3G Huawei USB dongle to connect to the internet a network camera

    I obtained from the provider a public IP address so than I can ping and find it on the internet.
    I forwarded the port assigned to the fixed IP address camera and even assigned a DMZ status to the camera

    However checking the port by:
    I always find it closed so that eventually connecting by a DDNS server doesn't work

    I read on a similar thread:
    that it's not necessary to forward a port when using a USB dongle
    Now how would the traffic directed to the camera be routed to its IP address?

    Any suggestion to solve the issue?

  2. #2
    Here is an troubleshooting instruction for port forwarding, you can have a look:

    Make sure the camera can be accessed internally via its IP plus port number first.
    Some camera has a fixed port number to be opened. Pay attention to the port number.
    And double check the internet/wan IP of the router is a public one.
    IP addresses below are private IP addresses:
    • - (65,536 IP addresses)
    • - (1,048,576 IP addresses)
    • - (16,777,216 IP addresses)

  3. #3
    thanks for answer
    I checked all items:
    - camera is accessed on internal network at
    - https://www.yougetsignal.com/tools/open-ports/
    provides me with the public IP address momentarily assigned:
    - so that I can ping from outside network to it successfully
    - checked port is correctly forwarded on router as specified in FAQ-785
    - however I CANNOT access from the network
    - and indeed https://www.yougetsignal.com/tools/open-ports/
    finds that port 1024 on my IP address is CLOSED

    Again the question is:
    DOES the Huawei USB dongle have an active role on stopping the traffic to the router?

    Unfortunately I can't find at its local address any way to set port forwarding or make a DMZ setting for the router at
    However I thought USB dongles should not affect traffic to the router

    thanks a lot for help

  4. #4
    DMZ IP address should be the IP address of your camera,
    The dongle is the internet source for the router. It does affect the traffic.
    Can you ping it seems this IP address is blocked.
    Is this IP address showing under 3G/4G or Internet part on the router's web management page or provided by your iSP directly?

  5. #5
    YES: DMZ IP address is the IP address of camera,
    YES: the dongle address: now is pingable from outside world:
    Risposta da byte=32 durata=283ms TTL=52
    and it is the public IP address of the SIM Modem Huawei E3131, as the screenshot shows:
    Name:  Screenshot 2017-11-01 17.18.20.png
Views: 0
Size:  70.5 KB

  6. #6
    However I read something more on coupling Huawei 3G USB dongles and routers and I understood there might be something else not working on transferring traffik from the dongle to the router due to the default setting of the dongle which is interfaced by a software "Hilink" rather than as a simple modem as it used to be in the past, pls see:

    so that it should be necessary to switch the modem from Hilink to modem mode

    Unfortunately I have also read some contrarian experience so that this action cannot revert the 3G dongle to the original mode eventually loosing its functionality.

    I wonder anybody has any experience on that and could help

  7. #7
    correct link is for suggestion to switch the 3G dongle to modem mode from Hilink:

    I saw it was cut

  8. #8
    The is the IP address of the dongle but the dongle will provide another IP address to the router.
    If the IP address provided to the router is not a public one, then port forwarding can't work.
    As you mentioned, change the dongle to modem mode may help.

  9. #9
    tried several methods to disable Hilink, did not succeed:

    because the COM ports are not shown on the device list

    and others are not effective for reasons cited in the link

    No way, hopeless adventure

  10. #10
    How about contacting the sim card provider for help?

  11. #11
    the SIM provider does not know about the modem one is using and they already helped providing immediately a public IP address for the SIM

    On the other hand I tried to contact Huawei support both by email and with FB messaging: so far no answer

    What about if I switch to 3G modem/router like the Huawei E5756?
    I would like to make sure that I can do port forwarding and dyndns
    but I CANNOT find the manual on the internet

    I wonder there is a more reliable 3G modem maker other than Huawei

    thanks anyway
    Last edited by stepic7; 11-06-2017 at 16:19.

  12. #12
    Perhaps Huawei support can help you to change the dongle to modem mode.


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