diff --git a/src/yggdrasil/tun_bsd.go b/src/yggdrasil/tun_bsd.go
index 5dbdd7d7..721b6778 100644
--- a/src/yggdrasil/tun_bsd.go
+++ b/src/yggdrasil/tun_bsd.go
@@ -137,7 +137,7 @@ func (tun *tunDevice) setupAddress(addr string) error {
 	copy(ar.ifr_name[:], tun.iface.Name())
 	ar.ifru_addr.sin6_len = uint8(unsafe.Sizeof(ar.ifru_addr))
 	ar.ifru_addr.sin6_family = unix.AF_INET6
-	parts := strings.Split(strings.TrimRight(addr, "/8"), ":")
+	parts := strings.Split(strings.Split(addr, "/")[0], ":")
 	for i := 0; i < 8; i++ {
 		addr, _ := strconv.ParseUint(parts[i], 16, 16)
 		b := make([]byte, 16)
diff --git a/src/yggdrasil/tun_darwin.go b/src/yggdrasil/tun_darwin.go
index 94a63de2..72b9cf08 100644
--- a/src/yggdrasil/tun_darwin.go
+++ b/src/yggdrasil/tun_darwin.go
@@ -84,7 +84,7 @@ func (tun *tunDevice) setupAddress(addr string) error {
 
 	ar.ifra_addr.sin6_len = uint8(unsafe.Sizeof(ar.ifra_addr))
 	ar.ifra_addr.sin6_family = unix.AF_INET6
-	parts := strings.Split(strings.TrimRight(addr, "/8"), ":")
+	parts := strings.Split(strings.Split(addr, "/")[0], ":")
 	for i := 0; i < 8; i++ {
 		addr, _ := strconv.ParseUint(parts[i], 16, 16)
 		b := make([]byte, 16)