Abstract: A traffic management apparatus for connection within a data transmission network is disclosed, that is arranged to manage the distribution of data traffic between data serving computers and the data relaying devices by analysing client requests. The apparatus has an input device (401), a data processing device (402) and an output device (403). The input device (401) is configured to receive electronic mail communications that include body text and one or more original file attachments in the form of executable programs. The processing device selects (803) original file attachments that are executable programs to produce selected file attachments. The processing device adds (805) a textural notice to the body text to the effect that an executable file is included as an attachment. The processing device compresses (806) the selected file attachment to produce compressed file attachments.