Non-Latin characters in username for FTP

Question

I tried to find the list of characters allowed in username for FTP but the RFC is not very specific. What ftp servers and clients support user names in Unicode? Special characters? Is there a generally accepted spec that explains the list of characters allowed in FTP usernames? (googling was of no help to me)

Answer 1

Try to encode using UTF-8 because most FTP servers will work with UTF-8.

Answer 2

RFC 959 5.3.2:

<username> ::= <string>
<string> ::= <char> | <char><string>
<char> ::= any of the 128 ASCII characters except <CR> and <LF>

Later RFCs (like proposed standard RFC 3659) talk about UTF-8 extensions, but only in the context of pathnames and file contents encoding.

So you can only depend on ASCII, but I suspect in practice most clients and servers support UTF-8.