| 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 |
| .BI "--reject-with " "type" |
| The type given can be |
| .nf |
| .B " icmp-net-unreachable" |
| .B " icmp-host-unreachable" |
| .B " icmp-port-unreachable" |
| .B " icmp-proto-unreachable" |
| .B " icmp-net-prohibited" |
| .B " icmp-host-prohibited or" |
| .B " icmp-admin-prohibited (*)" |
| .fi |
| which return the appropriate ICMP error message (\fBport-unreachable\fP is |
| the default). The option |
| .B tcp-reset |
| 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). |
| .TP |
| (*) Using icmp-admin-prohibited with kernels that do not support it will result in a plain DROP instead of REJECT |
