diff --git a/ipv6/control_stub.go b/ipv6/control_stub.go
index a045f28f..ca78a430 100644
--- a/ipv6/control_stub.go
+++ b/ipv6/control_stub.go
@@ -9,5 +9,5 @@ package ipv6
 import "golang.org/x/net/internal/socket"
 
 func setControlMessage(c *socket.Conn, opt *rawOpt, cf ControlFlags, on bool) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
diff --git a/ipv6/dgramopt.go b/ipv6/dgramopt.go
index eea4fde2..1f422e71 100644
--- a/ipv6/dgramopt.go
+++ b/ipv6/dgramopt.go
@@ -18,7 +18,7 @@ func (c *dgramOpt) MulticastHopLimit() (int, error) {
 	}
 	so, ok := sockOpts[ssoMulticastHopLimit]
 	if !ok {
-		return 0, errOpNoSupport
+		return 0, errNotImplemented
 	}
 	return so.GetInt(c.Conn)
 }
@@ -31,7 +31,7 @@ func (c *dgramOpt) SetMulticastHopLimit(hoplim int) error {
 	}
 	so, ok := sockOpts[ssoMulticastHopLimit]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	return so.SetInt(c.Conn, hoplim)
 }
@@ -44,7 +44,7 @@ func (c *dgramOpt) MulticastInterface() (*net.Interface, error) {
 	}
 	so, ok := sockOpts[ssoMulticastInterface]
 	if !ok {
-		return nil, errOpNoSupport
+		return nil, errNotImplemented
 	}
 	return so.getMulticastInterface(c.Conn)
 }
@@ -57,7 +57,7 @@ func (c *dgramOpt) SetMulticastInterface(ifi *net.Interface) error {
 	}
 	so, ok := sockOpts[ssoMulticastInterface]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	return so.setMulticastInterface(c.Conn, ifi)
 }
@@ -70,7 +70,7 @@ func (c *dgramOpt) MulticastLoopback() (bool, error) {
 	}
 	so, ok := sockOpts[ssoMulticastLoopback]
 	if !ok {
-		return false, errOpNoSupport
+		return false, errNotImplemented
 	}
 	on, err := so.GetInt(c.Conn)
 	if err != nil {
@@ -87,7 +87,7 @@ func (c *dgramOpt) SetMulticastLoopback(on bool) error {
 	}
 	so, ok := sockOpts[ssoMulticastLoopback]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	return so.SetInt(c.Conn, boolint(on))
 }
@@ -107,7 +107,7 @@ func (c *dgramOpt) JoinGroup(ifi *net.Interface, group net.Addr) error {
 	}
 	so, ok := sockOpts[ssoJoinGroup]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	grp := netAddrToIP16(group)
 	if grp == nil {
@@ -125,7 +125,7 @@ func (c *dgramOpt) LeaveGroup(ifi *net.Interface, group net.Addr) error {
 	}
 	so, ok := sockOpts[ssoLeaveGroup]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	grp := netAddrToIP16(group)
 	if grp == nil {
@@ -146,7 +146,7 @@ func (c *dgramOpt) JoinSourceSpecificGroup(ifi *net.Interface, group, source net
 	}
 	so, ok := sockOpts[ssoJoinSourceGroup]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	grp := netAddrToIP16(group)
 	if grp == nil {
@@ -167,7 +167,7 @@ func (c *dgramOpt) LeaveSourceSpecificGroup(ifi *net.Interface, group, source ne
 	}
 	so, ok := sockOpts[ssoLeaveSourceGroup]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	grp := netAddrToIP16(group)
 	if grp == nil {
@@ -189,7 +189,7 @@ func (c *dgramOpt) ExcludeSourceSpecificGroup(ifi *net.Interface, group, source
 	}
 	so, ok := sockOpts[ssoBlockSourceGroup]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	grp := netAddrToIP16(group)
 	if grp == nil {
@@ -210,7 +210,7 @@ func (c *dgramOpt) IncludeSourceSpecificGroup(ifi *net.Interface, group, source
 	}
 	so, ok := sockOpts[ssoUnblockSourceGroup]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	grp := netAddrToIP16(group)
 	if grp == nil {
@@ -233,7 +233,7 @@ func (c *dgramOpt) Checksum() (on bool, offset int, err error) {
 	}
 	so, ok := sockOpts[ssoChecksum]
 	if !ok {
-		return false, 0, errOpNoSupport
+		return false, 0, errNotImplemented
 	}
 	offset, err = so.GetInt(c.Conn)
 	if err != nil {
@@ -254,7 +254,7 @@ func (c *dgramOpt) SetChecksum(on bool, offset int) error {
 	}
 	so, ok := sockOpts[ssoChecksum]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	if !on {
 		offset = -1
@@ -269,7 +269,7 @@ func (c *dgramOpt) ICMPFilter() (*ICMPFilter, error) {
 	}
 	so, ok := sockOpts[ssoICMPFilter]
 	if !ok {
-		return nil, errOpNoSupport
+		return nil, errNotImplemented
 	}
 	return so.getICMPFilter(c.Conn)
 }
@@ -281,7 +281,7 @@ func (c *dgramOpt) SetICMPFilter(f *ICMPFilter) error {
 	}
 	so, ok := sockOpts[ssoICMPFilter]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	return so.setICMPFilter(c.Conn, f)
 }
@@ -295,7 +295,7 @@ func (c *dgramOpt) SetBPF(filter []bpf.RawInstruction) error {
 	}
 	so, ok := sockOpts[ssoAttachFilter]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	return so.setBPF(c.Conn, filter)
 }
diff --git a/ipv6/endpoint.go b/ipv6/endpoint.go
index 93257563..f534a0bf 100644
--- a/ipv6/endpoint.go
+++ b/ipv6/endpoint.go
@@ -37,7 +37,7 @@ func (c *Conn) PathMTU() (int, error) {
 	}
 	so, ok := sockOpts[ssoPathMTU]
 	if !ok {
-		return 0, errOpNoSupport
+		return 0, errNotImplemented
 	}
 	_, mtu, err := so.getMTUInfo(c.Conn)
 	if err != nil {
diff --git a/ipv6/genericopt.go b/ipv6/genericopt.go
index 1a18f754..0326aed6 100644
--- a/ipv6/genericopt.go
+++ b/ipv6/genericopt.go
@@ -12,7 +12,7 @@ func (c *genericOpt) TrafficClass() (int, error) {
 	}
 	so, ok := sockOpts[ssoTrafficClass]
 	if !ok {
-		return 0, errOpNoSupport
+		return 0, errNotImplemented
 	}
 	return so.GetInt(c.Conn)
 }
@@ -25,7 +25,7 @@ func (c *genericOpt) SetTrafficClass(tclass int) error {
 	}
 	so, ok := sockOpts[ssoTrafficClass]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	return so.SetInt(c.Conn, tclass)
 }
@@ -37,7 +37,7 @@ func (c *genericOpt) HopLimit() (int, error) {
 	}
 	so, ok := sockOpts[ssoHopLimit]
 	if !ok {
-		return 0, errOpNoSupport
+		return 0, errNotImplemented
 	}
 	return so.GetInt(c.Conn)
 }
@@ -50,7 +50,7 @@ func (c *genericOpt) SetHopLimit(hoplim int) error {
 	}
 	so, ok := sockOpts[ssoHopLimit]
 	if !ok {
-		return errOpNoSupport
+		return errNotImplemented
 	}
 	return so.SetInt(c.Conn, hoplim)
 }
diff --git a/ipv6/helper.go b/ipv6/helper.go
index 44b5866a..f767b1f5 100644
--- a/ipv6/helper.go
+++ b/ipv6/helper.go
@@ -15,7 +15,6 @@ var (
 	errMissingAddress  = errors.New("missing address")
 	errHeaderTooShort  = errors.New("header too short")
 	errInvalidConnType = errors.New("invalid conn type")
-	errOpNoSupport     = errors.New("operation not supported")
 	errNoSuchInterface = errors.New("no such interface")
 	errNotImplemented  = errors.New("not implemented on " + runtime.GOOS + "/" + runtime.GOARCH)
 )
diff --git a/ipv6/sockopt_posix.go b/ipv6/sockopt_posix.go
index 0eac86eb..409fdbfc 100644
--- a/ipv6/sockopt_posix.go
+++ b/ipv6/sockopt_posix.go
@@ -37,7 +37,7 @@ func (so *sockOpt) getICMPFilter(c *socket.Conn) (*ICMPFilter, error) {
 		return nil, err
 	}
 	if n != sizeofICMPv6Filter {
-		return nil, errOpNoSupport
+		return nil, errNotImplemented
 	}
 	return (*ICMPFilter)(unsafe.Pointer(&b[0])), nil
 }
@@ -54,7 +54,7 @@ func (so *sockOpt) getMTUInfo(c *socket.Conn) (*net.Interface, int, error) {
 		return nil, 0, err
 	}
 	if n != sizeofIPv6Mtuinfo {
-		return nil, 0, errOpNoSupport
+		return nil, 0, errNotImplemented
 	}
 	mi := (*ipv6Mtuinfo)(unsafe.Pointer(&b[0]))
 	if mi.Addr.Scope_id == 0 {
@@ -74,7 +74,7 @@ func (so *sockOpt) setGroup(c *socket.Conn, ifi *net.Interface, grp net.IP) erro
 	case ssoTypeGroupReq:
 		return so.setGroupReq(c, ifi, grp)
 	default:
-		return errOpNoSupport
+		return errNotImplemented
 	}
 }
 
diff --git a/ipv6/sockopt_stub.go b/ipv6/sockopt_stub.go
index 1f4a273e..d08e1bd2 100644
--- a/ipv6/sockopt_stub.go
+++ b/ipv6/sockopt_stub.go
@@ -14,33 +14,33 @@ import (
 )
 
 func (so *sockOpt) getMulticastInterface(c *socket.Conn) (*net.Interface, error) {
-	return nil, errOpNoSupport
+	return nil, errNotImplemented
 }
 
 func (so *sockOpt) setMulticastInterface(c *socket.Conn, ifi *net.Interface) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
 
 func (so *sockOpt) getICMPFilter(c *socket.Conn) (*ICMPFilter, error) {
-	return nil, errOpNoSupport
+	return nil, errNotImplemented
 }
 
 func (so *sockOpt) setICMPFilter(c *socket.Conn, f *ICMPFilter) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
 
 func (so *sockOpt) getMTUInfo(c *socket.Conn) (*net.Interface, int, error) {
-	return nil, 0, errOpNoSupport
+	return nil, 0, errNotImplemented
 }
 
 func (so *sockOpt) setGroup(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
 
 func (so *sockOpt) setSourceGroup(c *socket.Conn, ifi *net.Interface, grp, src net.IP) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
 
 func (so *sockOpt) setBPF(c *socket.Conn, f []bpf.RawInstruction) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
diff --git a/ipv6/sys_asmreq_stub.go b/ipv6/sys_asmreq_stub.go
index eece9618..9e77c85a 100644
--- a/ipv6/sys_asmreq_stub.go
+++ b/ipv6/sys_asmreq_stub.go
@@ -13,5 +13,5 @@ import (
 )
 
 func (so *sockOpt) setIPMreq(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
diff --git a/ipv6/sys_bpf_stub.go b/ipv6/sys_bpf_stub.go
index 676bea55..eb9f8316 100644
--- a/ipv6/sys_bpf_stub.go
+++ b/ipv6/sys_bpf_stub.go
@@ -12,5 +12,5 @@ import (
 )
 
 func (so *sockOpt) setAttachFilter(c *socket.Conn, f []bpf.RawInstruction) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
diff --git a/ipv6/sys_ssmreq_stub.go b/ipv6/sys_ssmreq_stub.go
index 581ee490..82e07c3b 100644
--- a/ipv6/sys_ssmreq_stub.go
+++ b/ipv6/sys_ssmreq_stub.go
@@ -13,9 +13,9 @@ import (
 )
 
 func (so *sockOpt) setGroupReq(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
-	return errOpNoSupport
+	return errNotImplemented
 }
 
 func (so *sockOpt) setGroupSourceReq(c *socket.Conn, ifi *net.Interface, grp, src net.IP) error {
-	return errOpNoSupport
+	return errNotImplemented
 }