On 2.5.2014, at 11.27, Atsuko Tanaka <tanaka@designet.co.jp> wrote:
We have currently set dovecot.sieve to insert the text "[SPAM]" at the beginning of an e-mail's subject when it's X-Spam-Score is above 80%. After we set our system as stated the following errors occur:
When an e-mail's subject contains control characters like [Ctrl+V|^V], dovecot.sieve terminates with an error and an e-mail is not able to be sent. When a MIME encoded Subject like [ＴＥＳＴ^VＭＡＩＬ] is sent we're not able to edit the subject and dovecot ends with an error. .. Aside from [Ctrl + V] the following control charcters also cause errors: backspace Ctrl + A Ctrl + C Ctrl + [ Ctrl + X Ctrl + Y
When an e-mail's subject line contains a "\0" character, everything following the null character is deleted.
Is there a reason why mails contain these kind of control characters? Is it commonly used? And is it OK if Dovecot translates them to UTF-8 for the rewritten header, or would the subject have to stay ISO-2022-JP encoded?