A method and arrangement (100) for impermanent connectivity between a client unit (110) and a server (120) in a network, comprising: at the client unit, a client proxy function (114) for receiving information from/for a client application (112), for storing said information, and for relaying said information between the client unit and the server when a connectivity link (130) therebetween is established. The arrangement may further comprise a server proxy function (124), and a messaging subsystem (116, 122). The information may be SMTP, POP3, HTTP or FTP information. An FTP file `GET` command may be performed by, in response to the `GET` command, writing a local file at the client unit having a unique signature, and when the connectivity link is established, obtaining the requested file from the server, finding the file at the client unit having the unique signature, and over-writing the found file with the obtained file. This provides the advantages that: client application code does not have to be modified operation is largely invisible to the client.