Re: [exim] strange spam

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Auteur: Renaud Allard
Datum:  
CC: Exim-users
Onderwerp: Re: [exim] strange spam


Vasiliy G Tolstov wrote:
> В Срд, 19/08/2009 в 11:15 +0200, Renaud Allard пишет:
>
>> Well, as it seems you also reject perfectly valid email addresses :)
>>
>>   v.tolstov@???
>>     SMTP error from remote mail server after RCPT TO:<v.tolstov@???>:
>>     host mx2.selfmail.ru [77.221.143.26]: 550 X-ACL-SMTP-MAIL:
>>     Invalid sender (<renaud/v.tolstov/selfip.ru/vuhgilkk@???>)

>
> Hm.. My condition is:
>
> ${if match {$sender_address_local_part}{\N^(\.|.+\.\.|.*[\%\/\!\&\$\@\|
> \~\`])\N} {yes}{no}}
>
> Why <renaud/v.tolstov/selfip.ru/vuhgilkk@???> is valid e-mail
> adaress?
>

Because RFC5321 (and 2821, 821) says so:

Here is what RFC says (I removed useless parts):

Reverse-path = Path / "<>"

Path           = "<" [ A-d-l ":" ] Mailbox ">"


A-d-l          = At-domain *( "," At-domain )
               ; Note that this form, the so-called "source
               ; route", MUST BE accepted, SHOULD NOT be
               ; generated, and SHOULD be ignored.


At-domain      = "@" Domain


Mailbox        = Local-part "@" ( Domain / address-literal )


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



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


Atom           = 1*atext



atext           =       ALPHA / DIGIT / ; Any character except controls,
                        "!" / "#" /     ;  SP, and specials.
                        "$" / "%" /     ;  Used for atoms
                        "&" / "'" /
                        "*" / "+" /
                        "-" / "/" /
                        "=" / "?" /
                        "^" / "_" /
                        "`" / "{" /
                        "|" / "}" /
                        "~"


So, basically, you can have a valid mailbox like this (without quotes)
"/dev/null.{tricky}@???"