Re: Which ICMP reject works best



Hello,

none a écrit :
Given the various iptables icmp reject types, which is suppose to make
the calling host shut up and go away the fastest ?

Valid reject types:
icmp-net-unreachable ICMP network unreachable
icmp-host-unreachable ICMP host unreachable
icmp-proto-unreachable ICMP protocol unreachable
icmp-port-unreachable ICMP port unreachable (default)
icmp-net-prohibited ICMP network prohibited
icmp-host-prohibited ICMP host prohibited
tcp-reset TCP RST packet
icmp-admin-prohibited ICMP administratively prohibited (*)

- TCP RST for TCP packets.
- ICMP Port Unreachable for UDP packets and other supported port-oriented protocols
- ICMP Protocol Unreachable for unsupported or non protocol-oriented protocols
- ICMP Communication Administratively Prohibited is nice but I have found that not all hosts understand it, which may reduce its efficiency.

Note : ICMP Network Prohibited and ICMP Host Prohibited are deprecated, ICMP Communication Administratively Prohibited must be used instead.

(Source : RFC 1812)
.



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