ICMP Types and Codes

Control messages

Control messages
Type	Code	Status	Description
0 Echo	0		Echo reply (used to ping)
1 and 2		unassigned	Reserved
3 – Destination Unreachable	0		Destination network unreachable
	1		Destination host unreachable
	2		Destination protocol unreachable
	3		Destination port unreachable
	4		Fragmentation required, and DF flag set
	5		Source route failed
	6		Destination network unknown
	7		Destination host unknown
	8		Source host isolated
	9		Network administratively prohibited
	10		Host administratively prohibited
	11		Network unreachable for ToS
	12		Host unreachable for ToS
	13		Communication administratively prohibited
	14		Host Precedence Violation
	15		Precedence cutoff in effect
4 – Source Quench	0	deprecated	Source quench (congestion control)
5 – Redirect Message	0		Redirect Datagram for the Network
	1		Redirect Datagram for the Host
	2		Redirect Datagram for the ToS & network
	3		Redirect Datagram for the ToS & host
6		deprecated	Alternate Host Address
7		unassigned	Reserved
8 – Echo Request	0		Echo request (used to ping)
9 – Router Advertisement	0		Router Advertisement
10 – Router Solicitation	0		Router discovery/selection/solicitation
11 – Time Exceeded	0		TTL expired in transit
11 – Time Exceeded	1		Fragment reassembly time exceeded
12 – Parameter Problem: Bad IP header	0		Pointer indicates the error
	1		Missing a required option
	2		Bad length
13 – Timestamp	0		Timestamp
14 – Timestamp Reply	0		Timestamp reply
15 – Information Request	0	deprecated	Information Request
16 – Information Reply	0	deprecated	Information Reply
17 – Address Mask Request	0	deprecated	Address Mask Request
18 – Address Mask Reply	0	deprecated	Address Mask Reply
19		reserved	Reserved for security
20 through 29		reserved	Reserved for robustness experiment
30 – Traceroute	0	deprecated	Information Request
31		deprecated	Datagram Conversion Error
32		deprecated	Mobile Host Redirect
33		deprecated	Where-Are-You (originally meant for IPv6)
34		deprecated	Here-I-Am (originally meant for IPv6)
35		deprecated	Mobile Registration Request
36		deprecated	Mobile Registration Reply
37		deprecated	Domain Name Request
38		deprecated	Domain Name Reply
39		deprecated	SKIP Algorithm Discovery Protocol, Simple Key-Management for Internet Protocol
40			Photuris, Security failures
41		experimental	ICMP for experimental mobility protocols such as Seamoby [RFC4065]
42 through 252		unassigned	Reserved
253		experimental	RFC3692-style Experiment 1 (RFC 4727)
254		experimental	RFC3692-style Experiment 2 (RFC 4727)
255		reserved	Reserved

Gurubaran

Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.