| diff --git a/scapy/contrib/mpls.py b/scapy/contrib/mpls.py | |
| index 640a0c5..6af1d4a 100644 | |
| --- a/scapy/contrib/mpls.py | |
| +++ b/scapy/contrib/mpls.py | |
| @@ -18,6 +18,8 @@ class MPLS(Packet): | |
| def guess_payload_class(self, payload): | |
| if len(payload) >= 1: | |
| + if not self.s: | |
| + return MPLS | |
| ip_version = (ord(payload[0]) >> 4) & 0xF | |
| if ip_version == 4: | |
| return IP |