  Quantum networks will allow to implement communication tasks beyond the reach
of their classical counterparts. A pressing and necessary issue for the design
of quantum network protocols is the quantification of the rates at which these
tasks can be performed. Here, we propose a simple recipe that yields
efficiently computable lower and upper bounds on the maximum achievable rates.
For this we make use of the max-flow min-cut theorem and its generalization to
multi-commodity flows to obtain linear programs. We exemplify our recipe
deriving the linear programs for bipartite settings, settings where multiple
pairs of users obtain entanglement in parallel as well as multipartite
settings, covering almost all known situations. We also make use of a
generalization of the concept of paths between user pairs in a network to
Steiner trees spanning a group of users wishing to establish
Greenberger-Horne-Zeilinger states.
