One or more techniques and/or systems are disclosed for identifying a list of destination servers ordered by round-trip time (RTT) for a requesting machine. When a client interacts with an address, such as an IP address, when accessing a remote service, an RTT is collected for the address, or the RTT may be derived for a range of addresses, and saved in a database. When the client subsequently requests access to a remote service, a list of destination servers are returned, respectively identified by corresponding addresses. The destination servers can be sorted in order of efficiency by determining an expected RTT associated with a matching address, or range, in the database, and sorting the destination servers by their respective expected RTTs.