.B " icmp6-port-unreachable"
.B " port-unreach"
.fi
-which return the appropriate IPv6-ICMP error message (\fBport-unreach\fP is
+which return the appropriate ICMPv6 error message (\fBport-unreach\fP is
the default). Finally, the option
.B tcp-reset
can be used on rules which only match the TCP protocol: this causes a
.I ident
(113/tcp) probes which frequently occur when sending mail to broken mail
hosts (which won't accept your mail otherwise).
+.B tcp-reset
+can only be used with kernel versions 2.6.14 or latter.