In this page of dotPeek options, you can define settings of the dotPeek symbol server.
|Generate symbol files (.pdb) for:||Using the radio buttons, choose assemblies for which symbol files should be generated. The meanings of the first four options are obvious. The last one allows for the most flexibility — after selecting this option, you can select only those assemblies which you need for debugging, and open them in the Assembly Explorer.|
dotPeek symbol server port. You may need to change the default port number if it is occupied by other application.