> Actually, I'm fairly certain this syntax is only valid in the To: or Cc:
> headers, not in any 'sender' header such as Reply-To.
Really no. RFC2822 (and older RFC822 too) defines that syntax only for
Reply-To header neither for From nor for Sender.
Here is shortcut from RFC2882:
-------------------------
from = "From:" mailbox-list CRLF
sender = "Sender:" mailbox CRLF
reply-to = "Reply-To:" address-list CRLF
address = mailbox / group
mailbox = name-addr / addr-spec
name-addr = [display-name] angle-addr
angle-addr = [CFWS] "<" addr-spec ">" [CFWS] / obs-angle-addr
group = display-name ":" [mailbox-list / CFWS] ";" [CFWS]
display-name = phrase
mailbox-list = (mailbox *("," mailbox)) / obs-mbox-list
address-list = (address *("," address)) / obs-addr-list
--------------------------
Only Reply-To supports "group" syntax.
I'v study this question accuratly because of blaming me as postmaster for
blocked mail.
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Sem.