The "ipv4options" module allows to match against a set of IPv4 header options. .TP \fB\-\-flags\fP [\fB!\fP]\fIsymbol\fP[\fB,\fP[\fB!\fP]\fIsymbol...\fP] Specify the options that shall appear or not appear in the header. Each symbol specification is delimited by a comma, and a '!' can be prefixed to a symbol to negate its presence. Symbols are either the name of an IPv4 option or its number. See examples below. .TP \fB\-\-any\fP By default, all of the flags specified must be present/absent, that is, they form an AND condition. Use the \-\-any flag instead to use an OR condition where only at least one symbol spec must be true. .PP Known symbol names (and their number): .PP 1 \(em \fBnop\fP .PP 2 \(em \fBsecurity\fP \(em RFC 1108 .PP 3 \(em \fBlsrr\fP \(em Loose Source Routing, RFC 791 .PP 4 \(em \fBtimestamp\fP \(em RFC 781, 791 .PP 7 \(em \fBrecord\-route\fP \em RFC 791 .PP 9 \(em \fBssrr\fP \(em Strict Source Routing, RFC 791 .PP 11 \(em \fBmtu\-probe\fP \(em RFC 1063 .PP 12 \(em \fBmtu\-reply\fP \(em RFC 1063 .PP 18 \(em \fBtraceroute\fP \(em RFC 1393 .PP 20 \(em \fBrouter-alert\fP \(em RFC 2113 .PP Examples: .PP Match packets that have both Timestamp and NOP: \-m ipv4options \-\-flags nop,timestamp .PP ~ that have either of Timestamp or NOP, or both: \-\-flags nop,timestamp \-\-any .PP ~ that have Timestamp and no NOP: \-\-flags '!nop,timestamp' .PP ~ that have either no NOP or a timestamp (or both conditions): \-\-flags '!nop,timestamp' \-\-any