Limitations

No limitation or range-checking is imposed by the API. However, users should be aware of the following size limitation on various elements of SMTP protocol. Sending data that exceed the limits may result in error returned by the server.

Table 65-2 SMTP Size Limitation

Element	Size Limitation
user	The maximum total length of a user name is 64 characters.
domain	The maximum total length of a domain name or number is 64 characters.
path	The maximum total length of a reverse-path or forward-path is 256 characters (including the punctuation and element separators).
command line	The maximum total length of a command line including the command word and the <CRLF> is 512 characters.
reply line	The maximum total length of a reply line including the reply code and the <CRLF> is 512 characters.
text line	The maximum total length of a text line including the <CRLF> is 1000 characters (but not counting the leading dot duplicated for transparency).
recipients buffer	The maximum total number of recipients that must be buffered is 100 recipients.