mda: attempt to prevent training loops

diff --git a/lib/PublicInbox/MDA.pm b/lib/PublicInbox/MDA.pm
index e2b2f9143083c0b1979d283fda7d2b985096e9a9..d2ce79eb210fe62b52160ab5ad0b08178e98d4a6 100644 (file)
--- a/lib/PublicInbox/MDA.pm
+++ b/lib/PublicInbox/MDA.pm
@@ -65,6 +65,9 @@ sub set_list_headers {
        $simple->header_set("List-Id", $pa);
        $simple->header_set("List-Post", $pa);
 
+       # prevent training loops
+       $simple->header_set('Delivered-To');
+
        my $url = $dst->{url};
        if (defined $url) {
                $simple->header_set("List-Archive", "<$url>");