FEATURE(accept_unqualified_senders)
The sendmail program refuses to
accept a message if the address specified as part of
an SMTP MAIL
From: command lacks a domain. That is,
if the address has a user part but lacks the
@ followed by a
domain, the message will be rejected:
MAIL From:<bob@foo.com> ← good, has a domain part MAIL From:<bob> ← bad, lacks a domain part
Some mail submission programs will submit mail without
including a domain part. Improperly configured PCs
are one example, as are poorly configured Unix
hosts. Generally, such problems will appear on your
local network. If you lack the authority to fix such
a problem, you can tweak
sendmail to accept such
addresses by including the FEATURE(accept_unqualified_senders)
like this:
FEATURE(`accept_unqualified_senders')
Note that this feature accepts unqualified addresses regardless of the port on which they are received. Such a broad solution might be acceptable on an internal network, but it is discouraged on machines that service the Internet. For those hosts, we recommend you tune acceptance or rejection of unqualified addresses on a port-by-port basis.
The DaemonPortOptions option u modifier (DaemonPortOptions=Modify=
on page 996), when set, has the same effect as
declaring this feature for the given single port.
That is, unqualified addresses are accepted on a
port-by-port basis, without the need to declare this
feature.
The DaemonPortOptions option f modifier (DaemonPortOptions=Modify=
on page 996), when set, tells
sendmail ...
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