OpenLink License Manager Networking Considerations If the License Manager discovers another License Manager is using a license with the same serial number, it will stop allocating licenses and report "License already in use".If the License Manager cannot communicate with the network, it will do the same.The OpenLink License Manager uses the multicast IP address 224.0.0.24 on ports 60001/udp and 60001/tcp to send and receive communications with other OpenLink components including other License Managers.It is becoming common for operating systems to have a default firewall enabled that blocks all network traffic, such that specific ports must be explicitly opened and/or applications must be explicitly granted communications permission. In such cases, port 60001 must be opened on both TCP and UDP, for both inbound and outbound communications, and/or oplmgr must be granted similar permissions. If you cannot figure out how to open this port in your local environment, please contact OpenLink Software Support for assistance. Related Documentation Firewall Considerations for Multi-Tier "Enterprise" Edition Data Access Drivers Configuring Server-side Firewalls for Multi-Tier Connectivity Error Message: Unable to contact the OpenLink License Manager Configure Multi-Tier Request Broker for Use on Machines with Multiple Network Cards