Many distributed services would benefit from control over the flow of traffic to and from their users, to offer better performance and higher reliability at a reasonable cost. Unfortunately, although today's cloud-computing platforms offer elastic computing and bandwidth resources, they do not give services control over wide-area routing. We propose replacing the data center's border router with a Transit Portal (TP) that gives each service the illusion of direct connectivity to upstream ISPs, without requiring each service to deploy hardware, acquire IP address space, or negotiate contracts with ISPs. Our TP prototype supports many layer-two connectivity mechanisms, amortizes memory and message overhead over multiple services, and protects the rest of the Internet from misconfigured and malicious applications. Our implementation extends and synthesizes open-source software components such as the Linux kernel and the Quagga routing daemon. We also implement a management plane based on the GENI control framework and couple this with our four-site TP deployment and Amazon EC2 facilities. Experiments with an anycast DNS application demonstrate the benefits the TP offers to distributed services.