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Toke Server Error - Server must be on the same subnet




  • Gurobot (AI-generated response)
    Gurobi Staff Gurobi Staff

    The error message you're seeing, "Server must be on the same subnet," typically suggests a networking configuration issue where the Gurobi token server and the client (your HPC) need to be able to communicate over a network that is configured to be on the same subnet. This can sometimes mean more than just being able to "ping" the server; the subnet configuration needs to align with specific networking requirements for Gurobi's licensing checks.

    In general, for Gurobi token servers:

    • Both the server and the client must be configured to be on the same subnet, which means they share the same network prefix. For example, if your subnet mask is, then the first three octets of the IP addresses should be the same.
    • There should not be any complex network configurations like NAT (Network Address Translation) between your token server and the clients that can prevent direct communication on the required ports.

    To resolve this issue:

    1. Check IP Configuration: Ensure both the token server and the HPC are on the same subnet as explained above. You might need to consult with your network administrator to confirm this.
    2. Firewall and Port Settings: Ensure that any firewalls between the server and the client are configured to allow traffic on the ports used by Gurobi (by default, port 41954). Both inbound and outbound rules should be checked.
    3. No Proxies/NAT: Verify that there is no NAT or proxy impacting the direct communication between the token server and the HPC.

    If adjustments to these settings do not resolve the issue, you might need to consider restructuring your network settings or placing the token server within the same local network as the HPC. If this does not help solve the issue, please create a support ticket in the Gurobi Help Centre explaining the issue. 

  • Thorsten Weiskopf
    First Comment
    First Question


    I just checked the server logs; the connection is working, as I have the logs with "not the same subnet on the token server", too. The HPC-Cluster itself has several subnets according to the definition above, and the computing nodes, which the users themselves can't choose, are on different subnets, too. I can't see a way to match the first three octets of the token server and HPC-Cluster. 

    Is there anything else we can do? 



    Thorsten Weiskopf 

  • Gwyneth Butera
    Gurobi Staff Gurobi Staff

    Hi Thorsten - As mentioned above,  please create a support ticket in the Gurobi Help Centre explaining the issue. -G


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