| This is used to send back an error packet in response to the matched |
| packet: otherwise it is equivalent to |
| .B DROP |
| so it is a terminating TARGET, ending rule traversal. |
| This target is only valid in the |
| .BR INPUT , |
| .B FORWARD |
| and |
| .B OUTPUT |
| chains, and user-defined chains which are only called from those |
| chains. The following option controls the nature of the error packet |
| returned: |
| .TP |
| \fB\-\-reject\-with\fP \fItype\fP |
| The type given can be |
| \fBicmp\-net\-unreachable\fP, |
| \fBicmp\-host\-unreachable\fP, |
| \fBicmp\-port\-unreachable\fP, |
| \fBicmp\-proto\-unreachable\fP, |
| \fBicmp\-net\-prohibited\fP, |
| \fBicmp\-host\-prohibited\fP, or |
| \fBicmp\-admin\-prohibited\fP (*), |
| which return the appropriate ICMP error message (\fBicmp\-port\-unreachable\fP is |
| the default). The option |
| \fBtcp\-reset\fP |
| can be used on rules which only match the TCP protocol: this causes a |
| TCP RST packet to be sent back. This is mainly useful for blocking |
| .I ident |
| (113/tcp) probes which frequently occur when sending mail to broken mail |
| hosts (which won't accept your mail otherwise). |
| .PP |
| (*) Using icmp\-admin\-prohibited with kernels that do not support it will result in a plain DROP instead of REJECT |
