F=X
Need RFC2821 hidden dot All versions
Delivery agents that speak SMTP require that any line
of the message that begins with a dot have that dot
doubled. Delivery agents speak SMTP or LMTP when the
$u
is missing
from the A=
delivery agent equate. For example:
Mether, P=[ICP], F=msDFMuCX, S=11, R=21, A=TCP $h
An example of a file that contains leading dots is a troff(1) source file:
.\" Show example .Ps Mether, P=[ICP], F=msDFMuCX, S=11, R=21, A=TCP $h .Pe
In this example, three lines begin with a leading dot,
but the F=X
delivery agent flag causes
sendmail to transmit the
message as:
.." Show example ..Ps Mether, P=[ICP], F=msDFMuCX, S=11, R=21, A=TCP $h ..Pe
The extra leading dot is automatically restored to a single dot at the receiving end.
This F=X
delivery
agent flag should be used only with delivery agents
that speak SMTP or LMTP. It should not be used with
other delivery agents because they will not know to
strip the extra dots.
Note that declaring FEATURE(local_lmtp)
causes this
F=X
delivery
agent flag to be automatically included for the
local
delivery
agent (as well as F=z
, F=z on
page 783).
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