| This allows you to match the ECN bits of the IPv4 and TCP header. ECN is the Explicit Congestion Notification mechanism as specified in RFC3168 | |
| .TP | |
| .BI "--ecn-tcp-cwr" | |
| This matches if the TCP ECN CWR (Congestion Window Received) bit is set. | |
| .TP | |
| .BI "--ecn-tcp-ece" | |
| This matches if the TCP ECN ECE (ECN Echo) bit is set. | |
| .TP | |
| .BI "--ecn-ip-ect " "num" | |
| This matches a particular IPv4 ECT (ECN-Capable Transport). You have to specify | |
| a number between `0' and `3'. |