If you want to determine the value for the client identifiers automatically, you do not need to perform this task. Proceed
to the Determining the Value for the DHCP Client Identifier Automatically Example section.
Tip |
If you are using AutoInstall to configure networking devices that are running a Cisco IOS release other than 12.4(1) or newer
the DHCP client identifier might use a different format. In this case use the process explained in the Determining the Vlaue
for the DHCP Client Identifier Automatically Example section.
|
You must know the MAC address of the Ethernet interface that will be used to connect the device to the LAN during the AutoInstall
process to determine the client identifier manually. To determine the client identifier manually requires connecting a terminal
to the device, and powering it on, so that you can enter the
show interface interface-type interface-number command.
The client-identifier looks like this:
0063.6973.636f.2d30.3030.362e.3533.6237.2e38.6537.312d.4661.332f.30
The format is nullcisco-0006.53b7.8e71-fa3/0 where 0006.53b7.8e71 is the MAC address and fa3/0 is the short interface name
for the interface that the IP address request is made.
The values for the short-if-name field can be obtained from an SNMP workstation with the Cisco MIBs installed. The following
is an example of how to map ifIndex to an interface on Cisco IOS:
snmpwalk -c public ponch ifName
IF-MIB::ifName.1 = STRING: AT2/0
IF-MIB::ifName.2 = STRING: Et0/0
IF-MIB::ifName.3 = STRING: Se0/0
IF-MIB::ifName.4 = STRING: BR0/0
Use the
show interface interface-type interface-number command to display the information and statistics for a Fast Ethernet interface.
R6> show interface fastethernet 3/0
FastEthernet3/0 is up, line protocol is up
Hardware is AmdFE, address is 0006.53b7.8e71 (bia 0006.53b7.8e71)
.
.
.
R6>
The MAC address for Fast Ethernet 3/0 on R6 is 0006.53b7.8e71. The format of the client identifier for this interface is
nullcisco-0006.53b7.8e71-fa3/0.
Note |
The short interface name for Fast Ethernet interfaces is fa.
|
The table below shows the values for converting characters to their hexadecimal equivalents. The last row in the second table
below shows the client identifier for Fast Ethernet 3/0 on R6 (nullcisco-0006.53b7.8e71-fa3/0).
Table 1. Hexadecimal to Character Conversion Chart
Hex
|
Char
|
Hex
|
Char
|
Hex
|
Char
|
Hex
|
Char
|
Hex
|
Char
|
00
|
NUL
|
1a
|
SUB
|
34
|
4
|
4e
|
N
|
68
|
h
|
01
|
SOH
|
1b
|
ESC
|
35
|
5
|
4f
|
O
|
69
|
I
|
02
|
STX
|
1c
|
FS
|
36
|
6
|
50
|
P
|
6a
|
j
|
03
|
ETX
|
1d
|
GS
|
37
|
7
|
51
|
Q
|
6b
|
k
|
04
|
EOT
|
1e
|
RS
|
38
|
8
|
52
|
R
|
6c
|
l
|
05
|
ENQ
|
1f
|
US
|
39
|
9
|
53
|
S
|
6d
|
m
|
06
|
ACK
|
20
|
|
3a
|
:
|
54
|
T
|
6e
|
n
|
07
|
BEL
|
21
|
!
|
3b
|
;
|
55
|
U
|
6f
|
o
|
08
|
BS
|
22
|
"
|
3c
|
<
|
56
|
V
|
70
|
p
|
09
|
TAB
|
23
|
#
|
3d
|
=
|
57
|
W
|
71
|
q
|
0A
|
LF
|
24
|
$
|
3e
|
>
|
58
|
X
|
72
|
r
|
0B
|
VT
|
25
|
%
|
3f
|
?
|
59
|
Y
|
73
|
s
|
0C
|
FF
|
26
|
&
|
40
|
@
|
5a
|
Z
|
74
|
t
|
0D
|
CR
|
27
|
‘
|
41
|
A
|
5b
|
[
|
75
|
u
|
0E
|
SO
|
28
|
(
|
42
|
B
|
5c
|
\
|
76
|
v
|
0F
|
SI
|
29
|
)
|
43
|
C
|
5d
|
]
|
77
|
w
|
10
|
DLE
|
2a
|
*
|
44
|
D
|
5e
|
^
|
78
|
x
|
11
|
DC1
|
2b
|
+
|
45
|
E
|
5f
|
_
|
79
|
y
|
12
|
DC2
|
2c
|
,
|
46
|
F
|
60
|
`
|
7a
|
z
|
13
|
DC3
|
2d
|
-
|
47
|
G
|
61
|
a
|
7b
|
{
|
14
|
DC4
|
2e
|
.
|
48
|
H
|
62
|
b
|
7c
|
|
|
15
|
NAK
|
2f
|
/
|
49
|
I
|
63
|
c
|
7D
|
}
|
16
|
SYN
|
30
|
0
|
4a
|
J
|
64
|
d
|
7e
|
~
|
17
|
ETB
|
31
|
1
|
4b
|
K
|
65
|
e
|
7f
|
D
|
18
|
CAN
|
32
|
2
|
4c
|
L
|
66
|
f
|
|
|
19
|
EM
|
33
|
3
|
4d
|
M
|
67
|
g
|
|
|
Table 2. Conversion of nullcisco-0006.53b7.8e71-fa3/0 To A Client Identifier
00
|
c
|
i
|
s
|
c
|
o
|
-
|
0
|
0
|
0
|
6
|
.
|
5
|
3
|
b
|
7
|
.
|
8
|
e
|
7
|
1
|
-
|
f
|
a
|
3
|
/
|
0
|
00
|
63
|
69
|
73
|
63
|
6f
|
2d
|
30
|
30
|
30
|
36
|
2e
|
35
|
33
|
62
|
37
|
2e
|
38
|
65
|
37
|
31
|
2d
|
46
|
61
|
33
|
2f
|
30
|
R4
Use the
show interface interface-type interface-number command to display the information and statistics for Ethernet 0 on R4.
R4> show interface ethernet 0
Ethernet0 is up, line protocol is up
Hardware is Lance, address is 00e0.1eb8.eb0e (bia 00e0.1eb8.eb0e)
The MAC address for Ethernet 0 on R4 is 00e0.1eb8.eb0e. The format of the client identifier for this interface is nullcisco-00e0.1eb8.eb0e-et0.
Note |
The short interface name for Ethernet interfaces is et.
|
Using the values for converting characters to their hexadecimal equivalents in the first table above, the client identifier
for Ethernet 0 on R4 is shown in the last row of the table below.
Table 3. Conversion of null.cisco-00e0.1eb8.eb0e-et0 To A Client Identifier for R4
00
|
c
|
i
|
s
|
c
|
o
|
-
|
0
|
0
|
e
|
0
|
.
|
1
|
e
|
b
|
8
|
.
|
e
|
b
|
0
|
e
|
-
|
e
|
t
|
0
|
00
|
63
|
69
|
73
|
63
|
6f
|
2d
|
30
|
30
|
65
|
30
|
2e
|
31
|
65
|
62
|
38
|
2e
|
65
|
62
|
30
|
65
|
2d
|
45
|
74
|
30
|
R3
Use the
show interface interface-type interface-number command to display the information and statistics for Ethernet 0 on R3.
R3> show interface ethernet 0
Ethernet0 is up, line protocol is up
Hardware is Lance, address is 00e0.1eb8.eb73 (bia 00e0.1eb8.eb73)
The MAC address for Ethernet 0 on R3 is 00e0.1eb8.eb73. The format of the client identifier for this interface is: nullcisco-00e0.1eb8.eb73-et0.
Using the values for converting characters to their hexadecimal equivalents in the first table above, the client identifier
for Ethernet 0 on R3 is shown in the last row of the table below.
Table 4. Conversion of null.cisco-00e0.1eb8.eb73-et0 To A Client Identifier for R3
00
|
c
|
i
|
s
|
c
|
o
|
-
|
0
|
0
|
e
|
0
|
.
|
1
|
e
|
b
|
8
|
.
|
e
|
b
|
7
|
3
|
-
|
e
|
t
|
0
|
00
|
63
|
69
|
73
|
63
|
6f
|
2d
|
30
|
30
|
65
|
30
|
2e
|
31
|
65
|
62
|
38
|
2e
|
65
|
62
|
37
|
33
|
2d
|
45
|
74
|
30
|
R2
Use the
show interface interface-type interface-number command to display the information and statistics for Ethernet 0 on R2.
R2> show interface ethernet 0
Ethernet0 is up, line protocol is up
Hardware is Lance, address is 00e0.1eb8.eb09 (bia 00e0.1eb8.eb09)
The MAC address for Ethernet 0 on R2 is 00e0.1eb8.eb09. The format of the client identifier for this interface is nullcisco-00e0.1eb8.eb09-et0.
Using the values for converting characters to their hexadecimal equivalents in the first table above, the client identifier
for Ethernet 0 on R2 is shown in the last row of the table below
Table 5. Conversion of null.cisco-00e0.1eb8.eb09-et0 To A Client Identifier for R2
00
|
c
|
i
|
s
|
c
|
o
|
-
|
0
|
0
|
e
|
0
|
.
|
1
|
e
|
b
|
8
|
.
|
e
|
b
|
0
|
9
|
-
|
e
|
t
|
0
|
00
|
63
|
69
|
73
|
63
|
6f
|
2d
|
30
|
30
|
65
|
30
|
2e
|
31
|
65
|
62
|
38
|
2e
|
65
|
62
|
30
|
39
|
2d
|
45
|
74
|
30
|
You have now determined the values for the client identifiers on each device. The final step is to add a period after each
group of four characters working from the left to the right as shown below:
-
R4-0063.6973.636f.2d30.3065.302e.3165.6238.2e65.6230.652d.4574.30
-
R3-0063.6973.636f.2d30.3065.302e.3165.6238.2e65.6237.332d.4574.30
-
R2-0063.6973.636f.2d30.3065.302e.3165.6238.2e65.6230.392d.4574.30