Abstract: At a migration server separate from a first server, a plurality of incoming internet protocol, IP, packets directed at an IP address associated with an IP service are received. On the basis of one or more source characteristics associated with IP packets in the plurality, it is determined that a first subset of packets in the plurality originated from one or more client devices which have not been migrated to a second server and that a second subset in the plurality originated from one or more client devices which have been migrated to the second server. IP packets determined to be in the first subset are forwarded to a first physical address associated with the first server for processing at the first server. IP packets determined to be in the second subset are processed at the second server.