Le 16/11/2010 20:50, Ralf Hildebrandt a écrit :
RCF 5321 says:4.5.3.1.1. Local-part The maximum total length of a user name or other local-part is 64 octets. RFC 2821 says: local-part The maximum total length of a user name or other local-part is 64 characters. RFC 821 says: user The maximum total length of a user name is 64 characters.
my understanding of these is: all implementations should support up to 64 chars at least. beyond that, nothing is guaranteed.
obviously, 64 is an arbitrary number. the fact that it is a power of two is not a valid excuse: nobody represents domains or local-parts as bits.
Ideally, there should be no limit. unfortunately, this is not reasonable in practice.
When I fed my postfix-2.8-20101108 (I'm using strict_rfc821_envelopes = yes) with this: # telnet localhost 10026 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 mail.charite.de ESMTP EHLO foo 250-mail.charite.de 250-PIPELINING 250-SIZE 26214400 250-ETRN 250-STARTTLS 250-XFORWARD NAME ADDR PROTO HELO SOURCE PORT IDENT 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN MAIL FROM:<> 250 2.1.0 Ok RCPT TO:<0123456789012345678901234567890123456789012345678901234567890123456...@example.com> 250 2.1.5 Ok RCPT TO:<0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456...@example.com> 250 2.1.5 Ok QUIT 221 2.0.0 Bye Connection closed by foreign host. I received no error message; but when using a domain literal exceeeding 63 characters I received an error.
that's part of the domain part validation code. I personally believe that this shouldn't be hardcoded. if one want to limit that, it's easily done with a regular expression.
On second thought, VERP is "encoding" the whole recipient address into the local part (of the sender address) when sending out mail; thus restricting the localpart to 64 characters would make little sense. But where IS the actual limit in postfix? max_line_lenght - lenght(RCPT TO:<>) ?
