diff --git a/doc/go1.3.txt b/doc/go1.3.txt
index 613d261974a7f..fda35a7e3ff8a 100644
--- a/doc/go1.3.txt
+++ b/doc/go1.3.txt
@@ -9,3 +9,4 @@ misc/benchcmp has been replaced by go tool benchcmp (CL 47980043)
 cmd/go, go/build: support .m files (CL 60590044)
 unicode: upgrade from Unicode 6.2.0 to 6.3.0 (CL 65400044)
 runtime/debug: add SetPanicOnFault (CL 66590044)
+crypto/tls: ServerName or InsecureSkipVerify (CL 67010043)
diff --git a/src/pkg/crypto/tls/handshake_client.go b/src/pkg/crypto/tls/handshake_client.go
index fd1303eebb947..0d8d9a1d46f9c 100644
--- a/src/pkg/crypto/tls/handshake_client.go
+++ b/src/pkg/crypto/tls/handshake_client.go
@@ -33,6 +33,10 @@ func (c *Conn) clientHandshake() error {
 		c.config = defaultConfig()
 	}
 
+	if len(c.config.ServerName) == 0 && !c.config.InsecureSkipVerify {
+		return errors.New("tls: either ServerName or InsecureSkipVerify must be specified in the tls.Config")
+	}
+
 	hello := &clientHelloMsg{
 		vers:                c.config.maxVersion(),
 		compressionMethods:  []uint8{compressionNone},