An e-mail server for communicating with a requestor of an e-mail message having a recipient username, the e-mail server comprising: a mail transport agent, MTA, configured to receive the e-mail message for an e-mail address comprising the username, the username including at least one non-ASCII character; a local delivery agent configured to store the received e-mail message in local storage; and a translation table configured to maintain a mapping from the username to a corresponding ASCII identifier having acceptable ASCII characters, the mapping from the username to the ASCII identifier being generated upon adding the username to the translation table, the ASCII identifier being compatible with an operating system of the e-mail server, the translation table being in communication with at least one of the MTA or the local delivery agent, wherein: the MTA either by itself or via the local delivery agent checks for existence of the recipient username against the translation table; the local delivery agent stores the received e-mail message in the local storage using the ASCII identifier if the existence of the username in the translation table is determined; and if the existence of the username in the translation table is not determined, rather than storing the received e-mail message by the local delivery agent, the MTA notifies the requestor of failure to locate the username in the translation table. a mail transport agent, MTA, configured to receive the e-mail message for an e-mail address comprising the username, the username including at least one non-ASCII character; a local delivery agent configured to store the received e-mail message in local storage; and a translation table configured to maintain a mapping from the username to a corresponding ASCII identifier having acceptable ASCII characters, the mapping from the username to the ASCII identifier being generated upon adding the username to the translation table, the ASCII identifier being compatible with an operating system of the e-mail server, the translation table being in communication with at least one of the MTA or the local delivery agent, wherein: the MTA either by itself or via the local delivery agent checks for existence of the recipient username against the translation table; the local delivery agent stores the received e-mail message in the local storage using the ASCII identifier if the existence of the username in the translation table is determined; and if the existence of the username in the translation table is not determined, rather than storing the received e-mail message by the local delivery agent, the MTA notifies the requestor of failure to locate the username in the translation table. the MTA either by itself or via the local delivery agent checks for existence of the recipient username against the translation table; the local delivery agent stores the received e-mail message in the local storage using the ASCII identifier if the existence of the username in the translation table is determined; and if the existence of the username in the translation table is not determined, rather than storing the received e-mail message by the local delivery agent, the MTA notifies the requestor of failure to locate the username in the translation table.