diff --git a/chain.go b/chain.go
index d8ca5ab..105f500 100644
--- a/chain.go
+++ b/chain.go
@@ -340,7 +340,9 @@ func (c *ProxyChain) getHttp2Conn(header http.Header) (net.Conn, error) {
 	return conn, nil
 }
 
-// Use HTTP2 as transport to connect target addr
+// Use HTTP2 as transport to connect target addr.
+//
+// BUG: SOCKS5 is ignored, only HTTP supported
 func (c *ProxyChain) http2Connect(addr string) (net.Conn, error) {
 	if !c.Http2Enabled() {
 		return nil, errors.New("HTTP2 is not enabled")
diff --git a/forward.go b/forward.go
index fcfd67f..b8601ac 100644
--- a/forward.go
+++ b/forward.go
@@ -111,6 +111,7 @@ func (node *cnode) run() {
 		lconn, err := net.ListenUDP("udp", nil)
 		if err != nil {
 			glog.V(LWARNING).Infof("[udp] %s -> %s : %s", node.srcAddr, node.dstAddr, err)
+			node.err = err
 			return
 		}
 		node.conn = lconn
@@ -118,6 +119,7 @@ func (node *cnode) run() {
 		tc, err := node.getUDPTunnel()
 		if err != nil {
 			glog.V(LWARNING).Infof("[udp-tun] %s -> %s : %s", node.srcAddr, node.dstAddr, err)
+			node.err = err
 			return
 		}
 		node.conn = tc
@@ -294,7 +296,7 @@ func (s *UdpForwardServer) ListenAndServe() error {
 			}
 			m[pkt.srcAddr.String()] = node
 			go node.run()
-			glog.V(LDEBUG).Infof("[udp] %s -> %s : new client (%d)", pkt.srcAddr, pkt.dstAddr, len(m))
+			glog.V(LINFO).Infof("[udp] %s -> %s : new client (%d)", pkt.srcAddr, pkt.dstAddr, len(m))
 		}
 
 		select {
diff --git a/socks.go b/socks.go
index 41fe5bd..97dc18a 100644
--- a/socks.go
+++ b/socks.go
@@ -546,6 +546,7 @@ func (s *Socks5Server) tunnelUDP(uc *net.UDPConn, cc net.Conn, client bool) (err
 		for {
 			n, addr, err := uc.ReadFromUDP(b)
 			if err != nil {
+				glog.V(LWARNING).Infof("[udp-tun] %s <- %s : %s", cc.RemoteAddr(), addr, err)
 				errc <- err
 				return
 			}
@@ -570,6 +571,7 @@ func (s *Socks5Server) tunnelUDP(uc *net.UDPConn, cc net.Conn, client bool) (err
 				dgram = gosocks5.NewUDPDatagram(
 					gosocks5.NewUDPHeader(uint16(n), 0, ToSocksAddr(addr)), b[:n])
 				if err := dgram.Write(cc); err != nil {
+					glog.V(LWARNING).Infof("[udp-tun] %s <- %s : %s", cc.RemoteAddr(), dgram.Header.Addr, err)
 					errc <- err
 					return
 				}
@@ -582,6 +584,7 @@ func (s *Socks5Server) tunnelUDP(uc *net.UDPConn, cc net.Conn, client bool) (err
 		for {
 			dgram, err := gosocks5.ReadUDPDatagram(cc)
 			if err != nil {
+				glog.V(LWARNING).Infof("[udp-tun] %s -> 0 : %s", cc.RemoteAddr(), err)
 				errc <- err
 				return
 			}
@@ -605,6 +608,7 @@ func (s *Socks5Server) tunnelUDP(uc *net.UDPConn, cc net.Conn, client bool) (err
 					continue // drop silently
 				}
 				if _, err := uc.WriteToUDP(dgram.Data, addr); err != nil {
+					glog.V(LWARNING).Infof("[udp-tun] %s -> %s : %s", cc.RemoteAddr(), addr, err)
 					errc <- err
 					return
 				}