lib/PublicInbox/MDA.pm | 3 ++-
 scripts/ssoma-replay   | 4 +++-
 t/httpd.t              | 2 +-
 t/nntpd.t              | 4 +++-

diff --git a/lib/PublicInbox/MDA.pm b/lib/PublicInbox/MDA.pm
index bcf5358bb6e6d7cd9e450e8f9c32c1db58f03ae1..6490102aaf8b3d52e6bcd680380a66507688fe82 100644
--- a/lib/PublicInbox/MDA.pm
+++ b/lib/PublicInbox/MDA.pm
@@ -78,7 +78,8 @@ sub set_list_headers {
 	my ($class, $simple, $dst) = @_;
 	unless (defined $simple->header('List-Id')) {
 		my $pa = $dst->{-primary_address};
-		$simple->header_set("List-Id", "<$pa>"); # RFC2919
+		$pa =~ tr/@/./; # RFC2919
+		$simple->header_set("List-Id", "<$pa>");
 	}
 
 	$simple->header_set($_) foreach @BAD_HEADERS;
diff --git a/scripts/ssoma-replay b/scripts/ssoma-replay
index 3c3fdf4857d239fe48462ffb72bc70950bae30d0..50bf45604b19aa7acefba902ebde6c86015bb304 100755
--- a/scripts/ssoma-replay
+++ b/scripts/ssoma-replay
@@ -45,7 +45,9 @@ my $body = $msg->body;
 my $list_id = $header_obj->header('List-Id');
 my ($archive_url, $user, $domain);
 if (defined $list_id) {
-	($user, $domain) = ($list_id =~ /<(.+)\@(.+)>/g);
+	# due to a bug in old versions of public-inbox, <user@domain> was used
+	# as the list-Id instead of <user.domain> as recommended in RFC2919
+	($user, $domain) = ($list_id =~ /<([^\.@]+)[\.@](.+)>/g);
 
 	if (defined $domain) {
 		$archive_url = "https://$domain/$user/";
diff --git a/t/httpd.t b/t/httpd.t
index c2e73608c90122c5a77246aca238a940929c740a..d0ce39432816896641b233466ff6245a9c47e134 100644
--- a/t/httpd.t
+++ b/t/httpd.t
@@ -57,7 +57,7 @@ Date: Thu, 01 Jan 1970 06:06:06 +0000
 
 nntp
 EOF
-		$mime->header_set('List-Id', "<$addr>");
+
 		my $git = PublicInbox::Git->new($maindir);
 		my $im = PublicInbox::Import->new($git, 'test', $addr);
 		$im->add($mime);
diff --git a/t/nntpd.t b/t/nntpd.t
index ad50a64fd7bb7b9d155bbdb339463db50476f72e..2ccc90fbad785254516f6c26c9e93e223e7abdda 100644
--- a/t/nntpd.t
+++ b/t/nntpd.t
@@ -62,7 +62,9 @@ Content-Transfer-Encoding: 8bit
 
 This is a test message for El\xc3\xa9anor
 EOF
-		$mime->header_set('List-Id', "<$addr>");
+		my $list_id = $addr;
+		$list_id =~ s/@/./;
+		$mime->header_set('List-Id', "<$list_id>");
 		$len = length($mime->as_string);
 		my $git = PublicInbox::Git->new($maindir);
 		my $im = PublicInbox::Import->new($git, 'test', $addr);