Blockage of communication links due to environmental obstructions and the resulting on/off channel behavior present challenges for providing reliable communication in mobile wireless networks. Traditional reliability techniques such as forward error correction and automatic repeat request (ARQ) are not designed to operate at the timescales typically observed in blockage channels. This work presents an approach to overcoming blockage that consists of multipath routing coupled with end-to-end rateless coding. In order to provide compatibility with operational IP networks as well as the possibility of incremental deployment, these techniques can be implemented as a routing overlay. We present algorithms to compute the maximum throughput achievable through this routing overlay approach, as well as a specific scheme to implement a multipath routing overlay in an IP network. Finally, we provide results from testing this approach on a mobile wireless network with satellite communication links. In our test scenario, satellite links suffer blockage from buildings in an urban setting. Our results characterize multipath routing overlay performance, which depends on the responsiveness of the underlay routing scheme.