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RED20 doesn't connect to the XG

Recently I purchased a RED20 to connect our branch office to HQ. The HQ has a Sophos XG firewall (XG310) which is all up to date.

When I try to connect the RED20 from the brach office to HQ no connection is being made.

What happens is this:

when booting the RED20 the system light starts blinking green and after a few seconds it's steady green and the router light starts blinking green.

After 70 seconds the router light dies and the system light turns red. This sequence keeps repeating itself.

The RED20 is connected directly to router and it should get an IP address from it.

On the XG I added a RED interface but it doesn't show any signs of connectivity with the RED20 (offline)

Does somebody have any clue why this isn't working?

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  • Hello Alex,

    Thank you for contacting the Sophos Community.

    Usually, that combination of lights might mean that the Default Gateway is unreachable. 

    If possible as a test I would recommend you to remove the Router where the RED is connecting and connect the RED directly to the internet line.

    Or if the router in front of the RED allows assigning a Static IP to the RED, try setting a static IP to the RED.

    You can also confirm if you see traffic arriving at the XG, by using the Public IP of the remote site as a host in the tcpdump. 

    tcpdump -eni any host 


    Emmanuel (EmmoSophos)
    Technical Team Lead, Global Community Support
    Sophos Support VideosProduct Documentation  |  @SophosSupport  | Sign up for SMS Alerts
    If a post solves your question use the 'Verify Answer' link.
  • Hello Emmanuel,

    Thanks for your reply.

    Unfortunately it isn't possible to connect the RED directly to the internet. But in the router I see the RED gets an IP-address assigned to it (DHCP client list).

    If I replace the RED with a laptop it gets also an IP-address, gateway-address and dns-server-addresses assigned to it.

    Tommorrow I will be on the remote location again and give the tcpdump a try.

    You also mentioned assigning a static IP-address to the RED. Can you tell me how that's be done?



  • Hello Alex,

    Thank you for the follow-up.

    To set the IP to the RED you do it from the XG, however, if the device is behind a NAT device, the RED will need an IP from that device to be able to go out the internet to reach the provisioning server.

    Once it connects the RED will pull down the configuration and create the tunnel with the XG. 

    For what you mentioned, most likely the RED is getting the IP, make sure also port port 3400 is open on the router in front of the RED and by your ISP. 

    You can test by running the following command from a computer behind your current NAT device

    telnet 3400

    You should see something like this:

    # telnet 3400
    Connected to
    Escape character is '^]'.


    Emmanuel (EmmoSophos)
    Technical Team Lead, Global Community Support
    Sophos Support VideosProduct Documentation  |  @SophosSupport  | Sign up for SMS Alerts
    If a post solves your question use the 'Verify Answer' link.
  • when testing on 3400 is successful from an other device, it may be this bug if you're on a lower version

    NRF-447 RED RED 20 devices were unable to connect to XG Firewall.

    fixed in 18 MR5 and 18.5 GA

  • Hello Emmanuel,

    It looks like there is nothing wrong with the connection to 

    When I try to telnet, as you suggested, the connection is established.

    Do you have any other suggestion?



  • Hi, I've checked the update status of the XG and it is fully updated.

    It seems like there is something blocking the access to on port 3400

  • with windows 10 a nice tool to test with is the powershell command tnc


    two examples for on tcp:3400

    PS > tnc -port 3400
    WARNUNG: TCP connect to ( : 3400) failed

    ComputerName           :
    RemoteAddress          :
    RemotePort             : 3400
    InterfaceAlias         : Ethernet
    SourceAddress          :
    PingSucceeded          : True
    PingReplyDetails (RTT) : 162 ms
    TcpTestSucceeded       : False

    PS > tnc -port 3400

    ComputerName     :
    RemoteAddress    :
    RemotePort       : 3400
    InterfaceAlias   : WLAN
    SourceAddress    :
    TcpTestSucceeded : True

    You need to check if there is some upsetream firewall blocking this port. As it is not widely used, there may be some 443 and basic web stuff enabled on your router or it's upstream firewall.

    Or your device is not masqued outside to the internet on the WAN router.

  • Hi LHerzog, 

    Thanks for your reply, that is a great way of checking.

    It's seems the connection from my network to is okay.  I don't see anything else in the router that might block outgoing traffic.

    Do you have any other suggestions?



  • I just checked the documentation:

    SD-RED 20 & SD-RED 60 uses TCP 3400 + UDP 3410

    You cannot check UDP with tnc by the way.

    Is this the first RED connecting to your XG?


    "RED is connecting to to get the config via port 3400. Then will connect to the XG hostname via 3400 and 3410."

    But from your description the RED internet LED will not light up, correct? So it cannot access Sophos Cloud.

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