This module matches packets related to a specific conntrack helper.
.TP
[\fB!\fP] \fB\-\-helper\fP \fIstring\fP
Matches packets related to the specified conntrack helper.
.RS
.PP
string can be "ftp" for packets related to an FTP session on default port.
For other ports, append \-\-portnr to the value, ie. "ftp\-2121".
.PP
Same rules apply for other conntrack helpers.
.RE