One-sided network communication technologies such as RDMA and NVMe-over-Fabrics are quickly gaining adoption in production software and in datacenters. Although appealing for their low CPU utilization and good performance, they raise new security concerns that could seriously undermine datacenter software systems building on top of them. At the same time, they offer unique opportunities to help enhance security. Indeed, one-sided network communication is a double-edged sword in security. This paper presents our insights into security implications and opportunities of one-sided communication.