A new utility program called MSU (mail server utility) is available that assists scientists in using electronic mail servers for sequence analysis, such as BLITZ, BLAST, GRAIL, etc. It is written in standard C and runs on various OpenVMS and UNIX platforms. In contrast to existing similar tools, MSU takes its knowledge about the request format a server expects from an external service description file. There's no in-built, hard-wired knowledge. This approach makes MSU extremely flexible and allows easy modification, extension and customisation. MSU is distributed with a default specification file that defines about twenty email services. New services can be added easily as they come up. When MSU starts up, it reads this file and creates a menu system which guides the user through the process of producing a well-formed service request. Additional options include the downloading of help files and the registration with services that require it prior to use. Most popular sequence formats are supported.