ICMP Types
Type
Code
Description
0
0
Echo Reply
3
  Destination Unreachable
 
0
Network unreachable
 
1
Host unreachable
 
2
Protocol unreachable
 
3
Port unreachable
 
4
Fragmentation needed but DF bit set
 
5
Source route failed
 
6
Destination network unknown
 
7
Destination host unknown
 
8
Source host isolated (obsolete)
 
9
Destination network administratively prohibited
 
10
Destination host administratively prohibited
 
11
Network unreachable to TOS
 
12
Host unreachable for TOS
 
13
Communication administratively prohibited
 
14
Host precedence violation
 
15
Precedence cutoff in effect
4
0
Source quench gateway requesting the host to reduce transfer rate
5   Redirect
 
0
Redirect for network
 
1
Redirect for host
 
2
Redirect for type-of-service and network
 
3
Redirect for type-of-service and host
8
0
Echo request
9
0
Router advertisement
10
0
Router solicitation
11
 
Time exceeded
 
0
TTL equals 0 during transit
 
1
TTL equals 0 during fragment reassembly
12
 
Parameter problem
 
0
IP header bad
 
1
Required option missing
13
0
Timestamp request
14
0
Timestamp reply
15
0
Information request
16
0
Information reply
17
0
Address mask request
18
0
Address mask reply