Книга: Linux Network Administrator Guide, Second Edition
ICMP datagram types
ICMP datagram types
Each of the firewall configuration commands allows you to specify ICMP datagram types. Unlike TCP and UDP ports, there is no convenient configuration file that lists the datagram types and their meanings. The ICMP datagram types are defined in RFC-1700, the Assigned Numbers RFC. The ICMP datagram types are also listed in one of the standard C library header files. The /usr/include/netinet/ip_icmp.h file, which belongs to the GNU standard library package and is used by C programmers when writing network software that uses the ICMP protocol, also defines the ICMP datagram types. For your convenience, we've listed them in Table 9.2. The iptables command interface allows you to specify ICMP types by name, so we've listed the mnemonics it uses, as well.
Table 9.2: ICMP Datagram Types
Type Number | iptables Mnemonic | Type Description |
---|---|---|
0 | echo-reply | Echo Reply |
3 | destination-unreachable | Destination Unreachable |
4 | source-quench | Source Quench |
5 | redirect | Redirect |
8 | echo-request | Echo Request |
11 | time-exceeded | Time Exceeded |
12 | parameter-problem | Parameter Problem |
13 | timestamp-request | Timestamp Request |
14 | timestamp-reply | Timestamp Reply |
15 | none | Information Request |
16 | none | Information Reply |
17 | address-mask-request | Address Mask Request |
18 | address-mask-reply | Address Mask Reply |