On Sun, 2021-04-04 at 07:03 -0600, Anthony J. Bentley wrote: > Hi, > > I had an interesting occurrence today... I was performing an action > that required a confirmation code from my bank, which they sent by > email. Unfortunately the mail never arrived, because: > > Apr 4 03:25:16 axx smtpd[59645]: fdc8f818f7adb2aa smtp failed-command > command="RCPT TO:<"username"@example.com>" > result="501 5.1.3 Recipient address syntax error" > > I assume the double quotes in there were the problem. I had to switch > to a GMail account to receive it. > Since everyone responding likes to point to what might be a nice and comfy workaround, let me take some inspiration from RFC5321.
>From section 3.3: RCPT TO:<forward-path> [ SP <rcpt-parameters> ] <CRLF> So let´s expand forward-path from section 4.1.2: Forward-path = Path Path = "<" [ A-d-l ":" ] Mailbox ">" Mailbox = Local-part "@" ( Domain / address-literal ) Local-part = Dot-string / Quoted-string ; MAY be case-sensitive Quoted-string = DQUOTE *QcontentSMTP DQUOTE In other words: the bank is correct (although maybe a little unusual) to use a double-quote surrounding the local-part. This should be fixed in smtpd. I´m not very familiar with that part of the code and I don´t know when I have the time to look into it. If anyone else beats me to this I would most welcome it. :-) martijn@