KOC256: asi nejlepsi je aplikovat postup z
RFC 5321, kde se v sekci 2.3.11 pise:
Consequently, and due to a long history of problems when intermediate hosts have attempted to optimize transport by modifying them, the local-part MUST be interpreted and assigned semantics only by the host specified in the domain part of the address., tedy vyhodnoceni platnosti local part by pri volnem vykladu tohoto pravidla bylo mozne nechat zcela na prijemci.