Added new Server field Hostname for the FQDN over the server (and updated various uses of the hostname). Moved Server.Addr to a parameter for ListenAndServe, as it was only used there.

envelope.go

@@ -15,7 +15,7 @@ type Envelope struct {
 }
 
 // AddReceivedLine prepends a Received header to the Data
-func (env *Envelope) AddReceivedLine(peer Peer, serverName string) {
+func (env *Envelope) AddReceivedLine(peer Peer) {
 
 	tlsDetails := ""
 
@@ -38,7 +38,7 @@ func (env *Envelope) AddReceivedLine(peer Peer, serverName string) {
 		"Received: from %s [%s] by %s with %s;%s\r\n\t%s\r\n",
 		peer.HeloName,
 		strings.Split(peer.Addr.String(), ":")[0],
-		serverName,
+		peer.ServerName,
 		peer.Protocol,
 		tlsDetails,
 		time.Now().Format("Mon Jan 2 15:04:05 -0700 2006"),

example_test.go

@@ -12,13 +12,11 @@ func ExampleServer() {
 
 	// No-op server. Accepts and discards
 	server = &smtpd.Server{}
-	server.ListenAndServe()
+	server.ListenAndServe("127.0.0.1:10025")
 
 	// Relay server. Accepts only from single IP address and forwards using the Gmail smtp
 	server = &smtpd.Server{
 
-		Addr: "0.0.0.0:10025",
-
 		HeloChecker: func(peer smtpd.Peer, name string) error {
 			if !strings.HasPrefix(peer.Addr.String(), "42.42.42.42:") {
 				return errors.New("Denied")
@@ -44,5 +42,5 @@ func ExampleServer() {
 		},
 	}
 
-	server.ListenAndServe()
+	server.ListenAndServe("127.0.0.1:10025")
 }

protocol.go

@@ -147,6 +147,8 @@ func (session *session) handleEHLO(cmd command) {
 	session.peer.HeloName = cmd.fields[1]
 	session.peer.Protocol = ESMTP
 
+	fmt.Fprintf(session.writer, "250-%s\r\n", session.server.Hostname)
+
 	extensions := session.extensions()
 
 	if len(extensions) > 1 {

smtpd.go

@@ -7,13 +7,12 @@ import (
 	"fmt"
 	"log"
 	"net"
-	"os"
 	"time"
 )
 
 // Server defines the parameters for running the SMTP server
 type Server struct {
-	Addr           string // Address to listen on when using ListenAndServe. (default: "127.0.0.1:10025")
+	Hostname       string // Server hostname. (default: "localhost.localdomain")
 	WelcomeMessage string // Initial server banner. (default: "<hostname> ESMTP ready.")
 
 	ReadTimeout  time.Duration // Socket timeout for read operations. (default: 60s)
@@ -58,12 +57,13 @@ const (
 
 // Peer represents the client connecting to the server
 type Peer struct {
-	HeloName string               // Server name used in HELO/EHLO command
+	HeloName   string               // Server name used in HELO/EHLO command
-	Username string               // Username from authentication, if authenticated
+	Username   string               // Username from authentication, if authenticated
-	Password string               // Password from authentication, if authenticated
+	Password   string               // Password from authentication, if authenticated
-	Protocol Protocol             // Protocol used, SMTP or ESMTP
+	Protocol   Protocol             // Protocol used, SMTP or ESMTP
-	Addr     net.Addr             // Network address
+	ServerName string               // A copy of Server.Hostname
-	TLS      *tls.ConnectionState // TLS Connection details, if on TLS
+	Addr       net.Addr             // Network address
+	TLS        *tls.ConnectionState // TLS Connection details, if on TLS
 }
 
 // Error represents an Error reported in the SMTP session.
@@ -97,7 +97,10 @@ func (srv *Server) newSession(c net.Conn) (s *session) {
 		conn:   c,
 		reader: bufio.NewReader(c),
 		writer: bufio.NewWriter(c),
-		peer:   Peer{Addr: c.RemoteAddr()},
+		peer: Peer{
+			Addr:       c.RemoteAddr(),
+			ServerName: srv.Hostname,
+		},
 	}
 
 	s.scanner = bufio.NewScanner(s.reader)
@@ -106,12 +109,12 @@ func (srv *Server) newSession(c net.Conn) (s *session) {
 
 }
 
-// ListenAndServe starts the SMTP server and listens on the address provided in Server.Addr
+// ListenAndServe starts the SMTP server and listens on the address provided
-func (srv *Server) ListenAndServe() error {
+func (srv *Server) ListenAndServe(addr string) error {
 
 	srv.configureDefaults()
 
-	l, err := net.Listen("tcp", srv.Addr)
+	l, err := net.Listen("tcp", addr)
 	if err != nil {
 		return err
 	}
@@ -195,20 +198,12 @@ func (srv *Server) configureDefaults() {
 		log.Fatal("Cannot use ForceTLS with no TLSConfig")
 	}
 
-	if srv.Addr == "" {
+	if srv.Hostname == "" {
-		srv.Addr = "127.0.0.1:10025"
+		srv.Hostname = "localhost.localdomain"
 	}
 
 	if srv.WelcomeMessage == "" {
-
+		srv.WelcomeMessage = fmt.Sprintf("%s ESMTP ready.", srv.Hostname)
-		hostname, err := os.Hostname()
-
-		if err != nil {
-			log.Fatal("Couldn't determine hostname: %s", err)
-		}
-
-		srv.WelcomeMessage = fmt.Sprintf("%s ESMTP ready.", hostname)
-
 	}
 
 }

smtpd_test.go

@@ -123,10 +123,10 @@ func TestListenAndServe(t *testing.T) {
 
 	ln.Close()
 
-	server := &smtpd.Server{Addr: addr}
+	server := &smtpd.Server{}
 
 	go func() {
-		server.ListenAndServe()
+		server.ListenAndServe(addr)
 	}()
 
 	time.Sleep(100 * time.Millisecond)
@@ -1158,8 +1158,9 @@ func TestEnvelopeReceived(t *testing.T) {
 	defer ln.Close()
 
 	server := &smtpd.Server{
+		Hostname: "foobar.example.net",
 		Handler: func(peer smtpd.Peer, env smtpd.Envelope) error {
-			env.AddReceivedLine(peer, "foobar.example.net")
+			env.AddReceivedLine(peer)
 			if !bytes.HasPrefix(env.Data, []byte("Received: from localhost [127.0.0.1] by foobar.example.net with ESMTP;")) {
 				t.Fatal("Wrong received line.")
 			}