iptables

// Посмотреть в таблице nat правила.
# iptables -t nat -L




$ cat /etc/protocols
# Internet (IP) protocols
#
# Updated from http://www.iana.org/assignments/protocol-numbers and other
# sources.
# New protocols will be added on request if they have been officially
# assigned by IANA and are not historical.
# If you need a huge list of used numbers please install the nmap package.

ip	0	IP		# internet protocol, pseudo protocol number
#hopopt	0	HOPOPT		# IPv6 Hop-by-Hop Option [RFC1883]
icmp	1	ICMP		# internet control message protocol
igmp	2	IGMP		# Internet Group Management
ggp	3	GGP		# gateway-gateway protocol
ipencap	4	IP-ENCAP	# IP encapsulated in IP (officially ``IP'')
st	5	ST		# ST datagram mode
tcp	6	TCP		# transmission control protocol
egp	8	EGP		# exterior gateway protocol
igp	9	IGP		# any private interior gateway (Cisco)
pup	12	PUP		# PARC universal packet protocol
udp	17	UDP		# user datagram protocol
hmp	20	HMP		# host monitoring protocol
xns-idp	22	XNS-IDP		# Xerox NS IDP
rdp	27	RDP		# "reliable datagram" protocol
iso-tp4	29	ISO-TP4		# ISO Transport Protocol class 4 [RFC905]
dccp	33	DCCP		# Datagram Congestion Control Prot. [RFC4340]
xtp	36	XTP		# Xpress Transfer Protocol
ddp	37	DDP		# Datagram Delivery Protocol
idpr-cmtp 38	IDPR-CMTP	# IDPR Control Message Transport
ipv6	41	IPv6		# Internet Protocol, version 6
ipv6-route 43	IPv6-Route	# Routing Header for IPv6
ipv6-frag 44	IPv6-Frag	# Fragment Header for IPv6
idrp	45	IDRP		# Inter-Domain Routing Protocol
rsvp	46	RSVP		# Reservation Protocol
gre	47	GRE		# General Routing Encapsulation
esp	50	IPSEC-ESP	# Encap Security Payload [RFC2406]
ah	51	IPSEC-AH	# Authentication Header [RFC2402]
skip	57	SKIP		# SKIP
ipv6-icmp 58	IPv6-ICMP	# ICMP for IPv6
ipv6-nonxt 59	IPv6-NoNxt	# No Next Header for IPv6
ipv6-opts 60	IPv6-Opts	# Destination Options for IPv6
rspf	73	RSPF CPHB	# Radio Shortest Path First (officially CPHB)
vmtp	81	VMTP		# Versatile Message Transport
eigrp	88	EIGRP		# Enhanced Interior Routing Protocol (Cisco)
ospf	89	OSPFIGP		# Open Shortest Path First IGP
ax.25	93	AX.25		# AX.25 frames
ipip	94	IPIP		# IP-within-IP Encapsulation Protocol
etherip	97	ETHERIP		# Ethernet-within-IP Encapsulation [RFC3378]
encap	98	ENCAP		# Yet Another IP encapsulation [RFC1241]
#	99			# any private encryption scheme
pim	103	PIM		# Protocol Independent Multicast
ipcomp	108	IPCOMP		# IP Payload Compression Protocol
vrrp	112	VRRP		# Virtual Router Redundancy Protocol [RFC5798]
l2tp	115	L2TP		# Layer Two Tunneling Protocol [RFC2661]
isis	124	ISIS		# IS-IS over IPv4
sctp	132	SCTP		# Stream Control Transmission Protocol
fc	133	FC		# Fibre Channel
mobility-header 135 Mobility-Header # Mobility Support for IPv6 [RFC3775]
udplite	136	UDPLite		# UDP-Lite [RFC3828]
mpls-in-ip 137	MPLS-in-IP	# MPLS-in-IP [RFC4023]
manet	138			# MANET Protocols [RFC5498]
hip	139	HIP		# Host Identity Protocol
shim6	140	Shim6		# Shim6 Protocol [RFC5533]
wesp	141	WESP		# Wrapped Encapsulating Security Payload
rohc	142	ROHC		# Robust Header Compression




$ iptables -p icmp --help
iptables v1.4.12

Usage: iptables -[ACD] chain rule-specification [options]
       iptables -I chain [rulenum] rule-specification [options]
       iptables -R chain rulenum rule-specification [options]
       iptables -D chain rulenum [options]
       iptables -[LS] [chain [rulenum]] [options]
       iptables -[FZ] [chain] [options]
       iptables -[NX] chain
       iptables -E old-chain-name new-chain-name
       iptables -P chain target [options]
       iptables -h (print this help information)

Commands:
Either long or short options are allowed.
  --append  -A chain		Append to chain
  --check   -C chain		Check for the existence of a rule
  --delete  -D chain		Delete matching rule from chain
  --delete  -D chain rulenum
				Delete rule rulenum (1 = first) from chain
  --insert  -I chain [rulenum]
				Insert in chain as rulenum (default 1=first)
  --replace -R chain rulenum
				Replace rule rulenum (1 = first) in chain
  --list    -L [chain [rulenum]]
				List the rules in a chain or all chains
  --list-rules -S [chain [rulenum]]
				Print the rules in a chain or all chains
  --flush   -F [chain]		Delete all rules in  chain or all chains
  --zero    -Z [chain [rulenum]]
				Zero counters in chain or all chains
  --new     -N chain		Create a new user-defined chain
  --delete-chain
            -X [chain]		Delete a user-defined chain
  --policy  -P chain target
				Change policy on chain to target
  --rename-chain
            -E old-chain new-chain
				Change chain name, (moving any references)
Options:
    --ipv4	-4		Nothing (line is ignored by ip6tables-restore)
    --ipv6	-6		Error (line is ignored by iptables-restore)
[!] --proto	-p proto	protocol: by number or name, eg. `tcp'
[!] --source	-s address[/mask][...]
				source specification
[!] --destination -d address[/mask][...]
				destination specification
[!] --in-interface -i input name[+]
				network interface name ([+] for wildcard)
 --jump	-j target
				target for rule (may load target extension)
  --goto      -g chain
                              jump to chain with no return
  --match	-m match
				extended match (may load extension)
  --numeric	-n		numeric output of addresses and ports
[!] --out-interface -o output name[+]
				network interface name ([+] for wildcard)
  --table	-t table	table to manipulate (default: `filter')
  --verbose	-v		verbose mode
  --line-numbers		print line numbers when listing
  --exact	-x		expand numbers (display exact values)
[!] --fragment	-f		match second or further fragments only
  --modprobe=		try to insert modules using this command
  --set-counters PKTS BYTES	set the counter during insert/append
[!] --version	-V		print package version.

icmp match options:
[!] --icmp-type typename	match icmp type
[!] --icmp-type type[/code]	(or numeric type or type/code)
Valid ICMP Types:
any
echo-reply (pong)
destination-unreachable
   network-unreachable
   host-unreachable
   protocol-unreachable
   port-unreachable
   fragmentation-needed
   source-route-failed
   network-unknown
   host-unknown
   network-prohibited
   host-prohibited
   TOS-network-unreachable
   TOS-host-unreachable
   communication-prohibited
   host-precedence-violation
   precedence-cutoff
source-quench
redirect
   network-redirect
   host-redirect
   TOS-network-redirect
   TOS-host-redirect
echo-request (ping)
router-advertisement
router-solicitation
time-exceeded (ttl-exceeded)
   ttl-zero-during-transit
   ttl-zero-during-reassembly
parameter-problem
   ip-header-bad
   required-option-missing
timestamp-request
timestamp-reply
address-mask-request
address-mask-reply