diff --git a/peerprotocol/extension.go b/peerprotocol/extension.go
index 7ab53ff..19b7799 100644
--- a/peerprotocol/extension.go
+++ b/peerprotocol/extension.go
@@ -16,9 +16,12 @@ package peerprotocol
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"errors"
+	"log"
 	"net"
 
+	"github.com/eyedeekay/sam3/i2pkeys"
 	"github.com/xgfone/bt/bencode"
 )
 
@@ -42,40 +45,83 @@ const (
 	UtMetadataExtendedMsgTypeReject  = 2 // BEP 9
 )
 
+const (
+	I2Plen = 32
+)
+
 // CompactIP is used to handle the compact ipv4 or ipv6.
-type CompactIP net.IP
+type CompactIP []byte
+
+func NewCompactIP(addr []byte) CompactIP {
+	switch len(addr) {
+	case net.IPv4len:
+		return CompactIP(addr)
+	case net.IPv6len:
+		return CompactIP(addr)
+	case I2Plen:
+		b := sha256.Sum256(addr)
+		return CompactIP(b[:])
+	default:
+		return nil
+	}
+}
 
 func (ci CompactIP) String() string {
-	return net.IP(ci).String()
+	switch len(ci) {
+	case net.IPv4len:
+		return net.IP(ci).String()
+	case net.IPv6len:
+		if ip := net.IP(ci).To4(); len(ip) != 0 {
+			return ip.String()
+		}
+		return "[" + net.IP(ci).String() + "]"
+	case I2Plen:
+		return i2pkeys.I2PAddr(ci).String()
+	default:
+		return ""
+	}
 }
 
 // MarshalBencode implements the interface bencode.Marshaler.
 func (ci CompactIP) MarshalBencode() ([]byte, error) {
-	ip := net.IP(ci)
-	if ipv4 := ip.To4(); len(ipv4) != 0 {
-		ip = ipv4
+	switch len(ci) {
+	case net.IPv4len:
+		ip := net.IP(ci)
+		if ipv4 := ip.To4(); len(ipv4) != 0 {
+			ip = ipv4
+		}
+		return bencode.EncodeBytes(ip[:])
+	case net.IPv6len:
+		ip := net.IP(ci)
+		if ipv4 := ip.To4(); len(ipv4) != 0 {
+			ip = ipv4
+		}
+		return bencode.EncodeBytes(ip[:])
+	case I2Plen:
+		ip := i2pkeys.I2PAddr(ci)
+		return bencode.EncodeBytes(ip[:])
+	default:
+		return nil, errInvalidIP
 	}
-	return bencode.EncodeBytes(ip[:])
+
 }
 
 // UnmarshalBencode implements the interface bencode.Unmarshaler.
 func (ci *CompactIP) UnmarshalBencode(b []byte) (err error) {
+	//var ip []byte //net.IP
 	var ip net.IP
 	if err = bencode.DecodeBytes(b, &ip); err != nil {
 		return
 	}
+	log.Println("LOG", ip)
 
 	switch len(ip) {
-	case net.IPv4len, net.IPv6len:
+	case net.IPv4len, net.IPv6len, I2Plen:
 	default:
 		return errInvalidIP
 	}
 
-	if ipv4 := ip.To4(); len(ipv4) != 0 {
-		ip = ipv4
-	}
-
-	*ci = CompactIP(ip)
+	*ci = NewCompactIP(ip)
 	return
 }
 
diff --git a/peerprotocol/extension_test.go b/peerprotocol/extension_test.go
index ffcbdfd..d47cd7e 100644
--- a/peerprotocol/extension_test.go
+++ b/peerprotocol/extension_test.go
@@ -29,7 +29,8 @@ func TestCompactIP(t *testing.T) {
 	var ip CompactIP
 	if err = ip.UnmarshalBencode(b); err != nil {
 		t.Error(err)
-	} else if ip.String() != "1.2.3.4" {
+	} else if ip.String() != "123.2.3.4" {
+		t.Log("IP", ip.String(), "IP")
 		t.Error(ip)
 	}
 }