libxt_tcpmss.man revision fea74bf74ff524431ce65145f1523584edf99dc9 
1This matches the TCP MSS (maximum segment size) field of the TCP header.  You can only use this on TCP SYN or SYN/ACK packets, since the MSS is only negotiated during the TCP handshake at connection startup time.
2.TP
3[\fB!\fP] \fB\-\-mss\fP \fIvalue\fP[\fB:\fP\fIvalue\fP]
4Match a given TCP MSS value or range.
5