diff --git a/ipv4/sys_windows.go b/ipv4/sys_windows.go
index b0913d5..955f7f4 100644
--- a/ipv4/sys_windows.go
+++ b/ipv4/sys_windows.go
@@ -25,16 +25,10 @@
 	sysIP_DROP_SOURCE_MEMBERSHIP = 0x10
 	sysIP_PKTINFO                = 0x13
 
-	sizeofInetPktinfo  = 0x8
 	sizeofIPMreq       = 0x8
 	sizeofIPMreqSource = 0xc
 )
 
-type inetPktinfo struct {
-	Addr    [4]byte
-	Ifindex int32
-}
-
 type ipMreq struct {
 	Multiaddr [4]byte
 	Interface [4]byte
@@ -61,7 +55,3 @@
 		ssoLeaveGroup:         {Option: socket.Option{Level: iana.ProtocolIP, Name: sysIP_DROP_MEMBERSHIP, Len: sizeofIPMreq}, typ: ssoTypeIPMreq},
 	}
 )
-
-func (pi *inetPktinfo) setIfindex(i int) {
-	pi.Ifindex = int32(i)
-}