A third-party email gateway relay is refusing to process a message for an email address we're sending to. The address is in the format of firstname..lastname@recipientdomain.com (note the two periods). Is this allowed by RFC guidelines?
RFC 2822 seems to object to this in section 3.4.1:
The locally interpreted string is either a quoted-string or a
dot-atom. If the string can be represented as a dot-atom (that is, it
contains no characters other than atext characters or "." surrounded
by atext characters), then the dot-atom form SHOULD be used and the
quoted-string form SHOULD NOT be used. Comments and folding white
space SHOULD NOT be used around the "@" in the addr-spec.
Furthermore, in that same section, it references this:
addr-spec = local-part "@" domain
local-part = dot-atom / quoted-string / obs-local-part
I interpret this to mean that the localpart can have content separated by dots but there cannot be two successive dots, and it cannot start or end with a dot. That being said, I'm not familiar with dot-atom syntax so maybe I'm mistaken here.
Can someone please confirm and explain?
Best Answer
Yes you are correct. The section you quoted says that it must be a quoted string OR a dot atom. Since its clearly not a quoted string (the lack of enclosing
"
makes that clear) it must be a dot-atom...That leads us to the definition of dot-atom:
Look at this except from RFC 5322 (3.2.3 - page 13) (RFC 2822 contains a similar section) the hint is the
1*
indot-atom-text = 1*atext *("." 1*atext)
. This effectively means that a dot-atom is made up of strings of one or more "atext" characters separated by dots. A string of 0 atext characters does not count and so you can not have two successive dots (seperated by 0 characters) or a leading or trailing dot.