[PATCH] git-send-email.perl: improve error message in send_message()

@@ -957,7 +957,10 @@ X-Mailer: git-send-email $gitversion
 		}
 
 		if (!$smtp) {
-			die "Unable to initialize SMTP properly.  Is there something wrong with your config?";
+			die "Unable to initialize SMTP properly. Check config. ",
+			    "VALUES: server=$smtp_server ",
+			    "encryption=$smtp_encryption ",
+			    defined $smtp_server_port ? "port=$smtp_server_port" : "";
 		}
 
 		if (defined $smtp_authuser) {

@@ -64,6 +64,7 @@ git send-email [options] <file | directory | rev-list options >
     --smtp-pass             <str>  * Password for SMTP-AUTH; not necessary.
     --smtp-encryption       <str>  * tls or ssl; anything else disables.
     --smtp-ssl                     * Deprecated. Use '--smtp-encryption ssl'.
+    --smtp-debug            <0|1>  * Disable, enable Net::SMTP debug.
 
   Automating:
     --identity              <str>  * Use the sendemail.<id> options.

@@ -187,6 +188,8 @@ my ($identity, $aliasfiletype, @alias_files, @smtp_host_parts);
 my ($validate, $confirm);
 my (@suppress_cc);
 
+my ($debug_net_smtp) = 0;		# Net::SMTP, see send_message()
+
 my $not_set_by_user = "true but not set by the user";
 
 my %config_bool_settings = (

@@ -270,6 +273,7 @@ my $rc = GetOptions("sender|from=s" => \$sender,
 		    "smtp-pass:s" => \$smtp_authpass,
 		    "smtp-ssl" => sub { $smtp_encryption = 'ssl' },
 		    "smtp-encryption=s" => \$smtp_encryption,
+		    "smtp-debug:i" => \$debug_net_smtp,
 		    "identity=s" => \$identity,
 		    "annotate" => \$annotate,
 		    "compose" => \$compose,

@@ -938,7 +942,8 @@ X-Mailer: git-send-email $gitversion
 			require Net::SMTP;
 			$smtp ||= Net::SMTP->new((defined $smtp_server_port)
 						 ? "$smtp_server:$smtp_server_port"
-						 : $smtp_server);
+						 : $smtp_server,
+						 Debug => $debug_net_smtp);
 			if ($smtp_encryption eq 'tls' && $smtp) {
 				require Net::SMTP::SSL;
 				$smtp->command('STARTTLS');

@@ -834,6 +834,46 @@ sub sanitize_address
 
 }
 
+# Returns the local Fully Qualified Domain Name (FQDN) if available,
+# If this is not given to EHLO, the receiving SMTP may deny connection
+# Here is an example of Net::SMTP without explicit Helo: it
+# uses by default "localhost.localdomain"
+#
+# Net::SMTP=GLOB(0x267ec28)>>> EHLO localhost.localdomain
+# Net::SMTP=GLOB(0x267ec28)<<< 550 EHLO argument does not match calling host
+
+sub maildomain ()
+{
+	my $maildomain;
+	eval "use Net::Domain";
+
+	unless ( $@ ) {
+		for my $host ( qw(mailhost localhost) ) {
+			my $smtp = Net::SMTP->new($host);
+			if (defined $smtp) {
+				my $domain = $smtp->domain;
+				$smtp->quit;
+
+				$maildomain = $domain
+					unless $^O eq 'darwin' && $domain =~ /\.local$/;
+
+				last if $maildomain;
+			}
+		}
+	}
+
+	unless ($maildomain) {
+		eval "use Net::Domain";
+		unless ( $@ ) {
+		    my $domain = Net::Domain::domainname();
+		    $maildomain = $domain
+			    unless $^O eq 'darwin' && $domain =~ /\.local$/;
+		}
+	}
+
+	$maildomain;
+}
+
 # Returns 1 if the message was sent, and 0 otherwise.
 # In actuality, the whole program dies when there
 # is an error sending a message.

@@ -917,6 +957,8 @@ X-Mailer: git-send-email $gitversion
 		}
 	}
 
+	my $maildomain;
+
 	if ($dry_run) {
 		# We don't want to send the email.
 	} elsif ($smtp_server =~ m#^/#) {

@@ -936,13 +978,18 @@ X-Mailer: git-send-email $gitversion
 		if ($smtp_encryption eq 'ssl') {
 			$smtp_server_port ||= 465; # ssmtp
 			require Net::SMTP::SSL;
-			$smtp ||= Net::SMTP::SSL->new($smtp_server, Port => $smtp_server_port);
+			$maildomain = maildomain() || "localhost.localdomain";
+			$smtp ||= Net::SMTP::SSL->new($smtp_server,
+						      Hello => $maildomain,
+						      Port => $smtp_server_port);
 		}
 		else {
 			require Net::SMTP;
+			$maildomain = maildomain() || "localhost.localdomain";
 			$smtp ||= Net::SMTP->new((defined $smtp_server_port)
 						 ? "$smtp_server:$smtp_server_port"
 						 : $smtp_server,
+						 Hello => $maildomain,
 						 Debug => $debug_net_smtp);
 			if ($smtp_encryption eq 'tls' && $smtp) {
 				require Net::SMTP::SSL;

@@ -962,9 +1009,10 @@ X-Mailer: git-send-email $gitversion
 		}
 
 		if (!$smtp) {
-			die "Unable to initialize SMTP properly. Check config. ",
+			die "Unable to initialize SMTP properly. Check config and use --smtp-debug. ",
 			    "VALUES: server=$smtp_server ",
 			    "encryption=$smtp_encryption ",
+			    "maildomain=$maildomain",
 			    defined $smtp_server_port ? "port=$smtp_server_port" : "";
 		}