1This module matches the parameters in Authentication header of IPsec packets.
2.TP
3.BR "--ahspi " "[!] \fIspi\fP[:\fIspi\fP]"
4Matches SPI.
5.TP
6.BR "--ahlen " "[!] \fIlength"
7Total length of this header in octets.
8.TP
9.BI "--ahres"
10Matches if the reserved field is filled with zero.
11