Usually in the Internet the local_part is simply the userid (e.g. pirx) or an easier to remember alias (e.g. Pirx.the.Pilot) as is the case in UIAH. The network part should then be a valid Internet Domain Address which is a hierarchy of strings separated with dots like KYBERIAS.UIAH.FI where FI is the two character ISO country code for Finland, UIAH the abbreviation of our organization and kyberias the name of the host. There can be many more levels of hierarchy but the top level domainis always the rightmost except in United Kingdom where they have reversed the order... E.g. An address postmaster@uk.ac.rl.ib is in Internet postmaster@ib.rl.ac.uk.