A SpecLog server allows you to share your repository over the network.
You do not require a server license to run a SpecLog server. The service will run without a license, however you will not be able to generate any authentication tokens on the server without a license. This means that access to the server is limited to users with a user license.
A user license permits you to access any SpecLog server. In order to access a server, you need to generate an authentication token on the client, transfer the token to the server, and register the token on the server.
You can find more information on registering tokens on the server and generating server tokens here.