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ICMP Message Types
This chapter lists and describes the possible ICMP message type resulting from a ping. The first three
columns list the possible symbol or type/code. For example, you would receive a ! or 03 as an echo reply
from your ping.
Table 1. ICMP Messages and Their Definitions
Symbol
Type
Code
Description
Query
Error
.
Timeout (no reply)
!
0
3
echo reply
.
U
3
destination unreachable:
0
network unreachable
.
1
host unreachable
.
2
protocol unreachable
.
3
port unreachable
.
4
fragmentation needed but don’t
fragment 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 for TOS
.
12
host unreachable for TOS
.
13
communication administratively
prohibited by filtering
.
14
host precedence violation
.
15
precedence cutoff in effect
.
C
4
0
source quench
.
5
redirect
.
ICMP Message Types
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