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Do this error was due to email client or

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tckoay View Drop Down

Joined: 02 April 2007
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    Posted: 08 June 2007 at 11:29pm

I notice some error from my log file as below

06/08/07 09:24:37:578 -- (1912) Mail from: To: '' - rejected - no relay allowed or % found in FROM address

This error was due to the TO email address carry with 2 '. I just wondering this error come from an email client or an email server that adding in the 2 ' into the email address.

Do this RFC compliant? Just want to get ready the info before customer shoot me.

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LogSat View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LogSat Quote  Post ReplyReply Direct Link To This Post Posted: 09 June 2007 at 5:49pm
I believe the single quote violates the RFC.

RFC 2821 ( states that the RCPT TO command must be specified as follows:
RCPT TO:<forward-path> [ SP <rcpt-parameters> ] <CRLF>

The first or only argument to this command includes a forward-path
(normally a mailbox and domain, always surrounded by "<" and ">"
brackets) identifying one recipient.

The question then becomes "how do you define a "forward-path". That is specified in the following section of the same RFC. Here's the relevant part. Please note that the key piece is the one at the bottom colored in purple, as it ultimately defines what the smaller piece of text can be. It states that the text can be delimited by a "DQUOTE" which is a double-quote, *NOT* by a single quote as in the case you saw.

4.1.2 Command Argument Syntax

The syntax of the argument fields of the above commands (using the
syntax specified in [8] where applicable) is given below. Some of
the productions given below are used only in conjunction with source
routes as described in appendix C. Terminals not defined in this
document, such as ALPHA, DIGIT, SP, CR, LF, CRLF, are as defined in
the "core" syntax [8 (section 6)] or in the message format syntax

Reverse-path = Path
Forward-path = Path
Path = "<" [ A-d-l ":" ] Mailbox ">"
A-d-l = At-domain *( "," A-d-l )
; Note that this form, the so-called "source route",
; MUST BE accepted, SHOULD NOT be generated, and SHOULD be
; ignored.
At-domain = "@" domain
Mail-parameters = esmtp-param *(SP esmtp-param)
Rcpt-parameters = esmtp-param *(SP esmtp-param)
esmtp-param = esmtp-keyword ["=" esmtp-value]
esmtp-keyword = (ALPHA / DIGIT) *(ALPHA / DIGIT / "-")
esmtp-value = 1*(%d33-60 / %d62-127)
; any CHAR excluding "=", SP, and control characters
Keyword = Ldh-str
Argument = Atom
Domain = (sub-domain 1*("." sub-domain)) / address-literal
sub-domain = Let-dig [Ldh-str]

address-literal = "[" IPv4-address-literal /
IPv6-address-literal /
General-address-literal "]"
; See section 4.1.3

Mailbox = Local-part "@" Domain

Local-part = Dot-string / Quoted-string
; MAY be case-sensitive

Dot-string = Atom *("." Atom)

Atom = 1*atext

Quoted-string = DQUOTE *qcontent DQUOTE

String = Atom / Quoted-string

Roberto Franceschetti

LogSat Software

Spam Filter ISP
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