What is the actual minimum length of an email address as defined by the IETF?

well the problem is really the question.. email depends on if it is sent over the internet, or within a closed system (eg intranet). over the internet, I believe [email protected] is the shortest email possible (e.g. google's G.CN for china would result in the shortest email adress possible, e.g. [email protected], which is 6 characters long). on the intranet however, it is an entirely different thing, and i@y would be possible, which is just 3 characters long.

The shortest valid email address may consist of only two parts: name and domain.

name@domain

Since both the name and domain may have the length of 1 character, the minimal total length resolves to 3 characters.