diff --git a/src/net/cgo_unix.go b/src/net/cgo_unix.go
index d9d5f0377c..cb89d65457 100644
--- a/src/net/cgo_unix.go
+++ b/src/net/cgo_unix.go
@@ -222,6 +222,11 @@ func cgoLookupPTR(addr string) ([]string, error, bool) {
 			break
 		}
 	}
+	// Add trailing dot to match pure Go reverse resolver
+	// and all other lookup routines. See golang.org/issue/12189.
+	if len(b) > 0 && b[len(b)-1] != '.' {
+		b = append(b, '.')
+	}
 	return []string{string(b)}, nil, true
 }
 
diff --git a/src/net/lookup_test.go b/src/net/lookup_test.go
index a42ae298ef..86957b5575 100644
--- a/src/net/lookup_test.go
+++ b/src/net/lookup_test.go
@@ -5,6 +5,7 @@
 package net
 
 import (
+	"bytes"
 	"fmt"
 	"strings"
 	"testing"
@@ -392,3 +393,111 @@ func TestLookupIPDeadline(t *testing.T) {
 	// happen due to issue 4856 for now.
 	t.Logf("%v succeeded, %v failed (%v timeout, %v temporary, %v other, %v unknown)", qstats.succeeded, qstats.failed, qstats.timeout, qstats.temporary, qstats.other, qstats.unknown)
 }
+
+func TestLookupDots(t *testing.T) {
+	if testing.Short() || !*testExternal {
+		t.Skipf("skipping external network test")
+	}
+
+	fixup := forceGoDNS()
+	defer fixup()
+	testDots(t, "go")
+
+	if forceCgoDNS() {
+		testDots(t, "cgo")
+	}
+}
+
+func testDots(t *testing.T, mode string) {
+	names, err := LookupAddr("8.8.8.8") // Google dns server
+	if err != nil {
+		t.Errorf("LookupAddr(8.8.8.8): %v (mode=%v)", err, mode)
+	} else {
+		for _, name := range names {
+			if !strings.HasSuffix(name, ".google.com.") {
+				t.Errorf("LookupAddr(8.8.8.8) = %v, want names ending in .google.com. with trailing dot (mode=%v)", names, mode)
+				break
+			}
+		}
+	}
+
+	cname, err := LookupCNAME("www.mit.edu")
+	if err != nil || !strings.HasSuffix(cname, ".") {
+		t.Errorf("LookupCNAME(www.mit.edu) = %v, %v, want cname ending in . with trailing dot (mode=%v)", cname, err, mode)
+	}
+
+	mxs, err := LookupMX("google.com")
+	if err != nil {
+		t.Errorf("LookupMX(google.com): %v (mode=%v)", err, mode)
+	} else {
+		for _, mx := range mxs {
+			if !strings.HasSuffix(mx.Host, ".google.com.") {
+				t.Errorf("LookupMX(google.com) = %v, want names ending in .google.com. with trailing dot (mode=%v)", mxString(mxs), mode)
+				break
+			}
+		}
+	}
+
+	nss, err := LookupNS("google.com")
+	if err != nil {
+		t.Errorf("LookupNS(google.com): %v (mode=%v)", err, mode)
+	} else {
+		for _, ns := range nss {
+			if !strings.HasSuffix(ns.Host, ".google.com.") {
+				t.Errorf("LookupNS(google.com) = %v, want names ending in .google.com. with trailing dot (mode=%v)", nsString(nss), mode)
+				break
+			}
+		}
+	}
+
+	cname, srvs, err := LookupSRV("xmpp-server", "tcp", "google.com")
+	if err != nil {
+		t.Errorf("LookupSRV(xmpp-server, tcp, google.com): %v (mode=%v)", err, mode)
+	} else {
+		if !strings.HasSuffix(cname, ".google.com.") {
+			t.Errorf("LookupSRV(xmpp-server, tcp, google.com) returned cname=%v, want name ending in .google.com. with trailing dot (mode=%v)", cname, mode)
+		}
+		for _, srv := range srvs {
+			if !strings.HasSuffix(srv.Target, ".google.com.") {
+				t.Errorf("LookupSRV(xmpp-server, tcp, google.com) returned addrs=%v, want names ending in .google.com. with trailing dot (mode=%v)", srvString(srvs), mode)
+				break
+			}
+		}
+	}
+}
+
+func mxString(mxs []*MX) string {
+	var buf bytes.Buffer
+	sep := ""
+	fmt.Fprintf(&buf, "[")
+	for _, mx := range mxs {
+		fmt.Fprintf(&buf, "%s%s:%d", sep, mx.Host, mx.Pref)
+		sep = " "
+	}
+	fmt.Fprintf(&buf, "]")
+	return buf.String()
+}
+
+func nsString(nss []*NS) string {
+	var buf bytes.Buffer
+	sep := ""
+	fmt.Fprintf(&buf, "[")
+	for _, ns := range nss {
+		fmt.Fprintf(&buf, "%s%s", sep, ns.Host)
+		sep = " "
+	}
+	fmt.Fprintf(&buf, "]")
+	return buf.String()
+}
+
+func srvString(srvs []*SRV) string {
+	var buf bytes.Buffer
+	sep := ""
+	fmt.Fprintf(&buf, "[")
+	for _, srv := range srvs {
+		fmt.Fprintf(&buf, "%s%s:%d:%d:%d", sep, srv.Target, srv.Port, srv.Priority, srv.Weight)
+		sep = " "
+	}
+	fmt.Fprintf(&buf, "]")
+	return buf.String()
+}
diff --git a/src/net/non_unix_test.go b/src/net/non_unix_test.go
new file mode 100644
index 0000000000..eddca562f9
--- /dev/null
+++ b/src/net/non_unix_test.go
@@ -0,0 +1,11 @@
+// Copyright 2015 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build nacl plan9 windows
+
+package net
+
+// See unix_test.go for what these (don't) do.
+func forceGoDNS() func() { return func() {} }
+func forceCgoDNS() bool  { return false }
diff --git a/src/net/unix_test.go b/src/net/unix_test.go
index 59f5c2d85b..358ff31072 100644
--- a/src/net/unix_test.go
+++ b/src/net/unix_test.go
@@ -404,3 +404,28 @@ func TestUnixgramConnLocalAndRemoteNames(t *testing.T) {
 		}
 	}
 }
+
+// forceGoDNS forces the resolver configuration to use the pure Go resolver
+// and returns a fixup function to restore the old settings.
+func forceGoDNS() func() {
+	c := systemConf()
+	oldGo := c.netGo
+	oldCgo := c.netCgo
+	fixup := func() {
+		c.netGo = oldGo
+		c.netCgo = oldCgo
+	}
+	c.netGo = true
+	c.netCgo = false
+	return fixup
+}
+
+// forceCgoDNS forces the resolver configuration to use the cgo resolver
+// and returns true to indicate that it did so.
+// (On non-Unix systems forceCgoDNS returns false.)
+func forceCgoDNS() bool {
+	c := systemConf()
+	c.netGo = false
+	c.netCgo = true
+	return true
+}