Information Technology Reference
In-Depth Information
Table 23.1
Message type field value
Value
Description
Code field
Additional information
0
Echo reply message
0
16-bit identifier
16-bit sequence number
3
Destination
Unreachable
0 = net unreachable
1 = host unreachable
2 = protocol unreachable
3 = port unreachable
4 = fragmentation needed
and D bit set
5 = source route failed
32 bits unused.
Internet header + 64 bits of
original data datagram
4
Source quench
message
0
32 bits unused.
Internet header + 64 bits of
original data datagram
5
Redirect message
0 = redirect datagram for
the network
1 = redirect datagram for
the host
2 = redirect datagram for
the type of service and
network
3 = redirect datagram for
the type of service and
host
32 bits gateway address.
Internet header + 64 bits of
original data datagram
8
Echo request
0
11
Time-to-live
exceeded
0 = time-to-live exceeded in
transit
1 = fragment reassembly
time exceeded
32 bits unused.
Internet header + 64 bits of
original data datagram
12
Parameter problem
0 = pointer indicates the
error
8-bit pointer.
24 bits unused.
Internet header + 64 bits of
original data datagram
13
Timestamp request
0
16-bit identifier
16-bit sequence number
32-bit originate timestamp
32-bit receive timestamp
32-bit transmit timestamp
14
Timestamp reply
0
As above
15
Information request
0
16-bit identifier
16-bit sequence number
16
Information reply
0
As above
