1

I am trying to configure DHCP Server on a Cisco 2960-X switch to achieve port-based address allocation. I would like the IP address assigned to any device connected to that port to be the same every time.

I have used the following guide to achieve this: Configuring DHCP Features and IP Source Guard

The commands used are explained in detail here: Cisco IOS IP Addressing Services Command Reference

I have also tried various iterations of the following command to find something that works: address ip-address client-id string [ascii]

What I am not sure about is the string after client-id. Does it have to match your interface name? If not how does the DHCP server know which interface to relate the assigned IP address.

Here's my running-config:

otg#show vlan

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Gi1/0/1, Gi1/0/3, Gi1/0/4
                                                Gi1/0/5, Gi1/0/6, Gi1/0/7
                                                Gi1/0/8, Gi1/0/9, Gi1/0/10
                                                Gi1/0/11, Gi1/0/12, Gi1/0/13
                                                Gi1/0/14, Gi1/0/15, Gi1/0/16
                                                Gi1/0/17, Gi1/0/18, Gi1/0/19
                                                Gi1/0/20, Gi1/0/21, Gi1/0/22
                                                Gi1/0/23, Gi1/0/24, Gi1/0/25
                                                Gi1/0/26, Gi1/0/27, Gi1/0/28
2    VLAN0002                         active    Gi1/0/2
140  VLAN0140                         active
1002 fddi-default                     act/unsup
1003 token-ring-default               act/unsup
1004 fddinet-default                  act/unsup
1005 trnet-default                    act/unsup

VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1    enet  100001     1500  -      -      -        -    -        0      0
2    enet  100002     1500  -      -      -        -    -        0      0

VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
140  enet  100140     1500  -      -      -        -    -        0      0
1002 fddi  101002     1500  -      -      -        -    -        0      0
1003 tr    101003     1500  -      -      -        -    -        0      0
1004 fdnet 101004     1500  -      -      -        ieee -        0      0
1005 trnet 101005     1500  -      -      -        ibm  -        0      0

Remote SPAN VLANs
------------------------------------------------------------------------------


Primary Secondary Type              Ports
------- --------- ----------------- ------------------------------------------

---------------------------------------------------------------------------------------------------------------------

otg#show ip dhcp pool

Pool otgpool :
 Utilization mark (high/low)    : 100 / 0
 Subnet size (first/next)       : 0 / 0
 Total addresses                : 254
 Leased addresses               : 0
 Excluded addresses             : 1
 Pending event                  : none
 1 subnet is currently in the pool :
 Current index        IP address range                    Leased/Excluded/Total
 192.168.100.1        192.168.100.1    - 192.168.100.254   0     / 1     / 254
 1 reserved address is currently in the pool :
 Address          Client
 192.168.100.100  Gi1/0/2

---------------------------------------------------------------------------------------------------------------------

otg#sh run
Building configuration...


Current configuration : 4058 bytes
!
! Last configuration change at 06:04:30 UTC Tue Jan 5 2016
! NVRAM config last updated at 23:29:56 UTC Mon Jan 4 2016
!
version 15.0
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname otg
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$43Kk$SyzqQc5biarBjD2TD9Hw0/
enable password otgswitch
!
no aaa new-model
clock timezone UTC -5 0
clock summer-time UTC recurring
switch 1 provision ws-c2960x-24ts-l
ip dhcp use subscriber-id client-id
ip dhcp subscriber-id interface-name
!
ip dhcp pool otgpool
 network 192.168.100.0 255.255.255.0
 default-router 192.168.100.1
 reserved-only
   address 192.168.100.100 client-id "Gi1/0/2" ascii
!
!
!
!
crypto pki trustpoint TP-self-signed-1160303744
 enrollment selfsigned
 subject-name cn=IOS-Self-Signed-Certificate-1160303744
 revocation-check none
 rsakeypair TP-self-signed-1160303744
!
!
crypto pki certificate chain TP-self-signed-1160303744
 certificate self-signed 01
  3082022B 30820194 A0030201 02020101 300D0609 2A864886 F70D0101 05050030
  31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274
  69666963 6174652D 31313630 33303337 3434301E 170D3136 30313035 30343239
  35365A17 0D323030 31303130 30303030 305A3031 312F302D 06035504 03132649
  4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D31 31363033
  30333734 3430819F 300D0609 2A864886 F70D0101 01050003 818D0030 81890281
  810081CE C80CB939 C1722AA5 E3167E22 23DE4A5F EBB8168C 0DEF4392 F4624590
  11282956 58E0A473 806BBC5E 65E228F4 8FF553ED B1A07A46 CBBC80BA 22C16838
  11EEFA3B 9CD7290D D79CAEDC 4F259F57 8F30CC84 6125CD18 90917913 ECE9B8BA
  DE9F2BDC 21F62BCC 424D5D19 8FEEE8F5 E5A86568 DAF3EE8A 4CD5BE74 63E14AED
  C9BB0203 010001A3 53305130 0F060355 1D130101 FF040530 030101FF 301F0603
  551D2304 18301680 14E50E89 9DFB34B0 F88C367D D1DFE392 1849468B BC301D06
  03551D0E 04160414 E50E899D FB34B0F8 8C367DD1 DFE39218 49468BBC 300D0609
  2A864886 F70D0101 05050003 81810077 5FCAF4BC 7ABCDE2E 69FFB95E 1BBE6CE6
  584B0392 998CD1FB 226E9767 F400304B 36C1692F 54B4CF09 F461AE69 097E47F3
  64D8EB80 4CDB1E87 0FD375A7 DF45B8B0 72B6630E 5D29A00A 1679F321 CBED7B18
  370AC2D0 D8DD2DA5 AF7FECFD 44DE20D0 6D991B2F BFDA7E64 791ACC01 22031B34
  7C1FB7EC C2EAD9DC 45CB4261 00795F
        quit
spanning-tree mode pvst
spanning-tree extend system-id
!
!
!
!
!
!
vlan internal allocation policy ascending
!
!
!
!
!
!
interface FastEthernet0
 no ip address
!
interface GigabitEthernet1/0/1
!
interface GigabitEthernet1/0/2
 description cart2
 switchport access vlan 2
 switchport mode access
 switchport port-security maximum 2
 switchport port-security
 ip dhcp server use subscriber-id client-id
 storm-control broadcast level 10.00
 storm-control multicast level 10.00
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/3
!
interface GigabitEthernet1/0/4
!
interface GigabitEthernet1/0/5
!
interface GigabitEthernet1/0/6
!
interface GigabitEthernet1/0/7
!
interface GigabitEthernet1/0/8
!
interface GigabitEthernet1/0/9
!
interface GigabitEthernet1/0/10
!
interface GigabitEthernet1/0/11
!
interface GigabitEthernet1/0/12
!
interface GigabitEthernet1/0/13
!
interface GigabitEthernet1/0/14
!
interface GigabitEthernet1/0/15
!
interface GigabitEthernet1/0/16
!
interface GigabitEthernet1/0/17
!
interface GigabitEthernet1/0/18
!
interface GigabitEthernet1/0/19
!
interface GigabitEthernet1/0/20
!
interface GigabitEthernet1/0/21
!
interface GigabitEthernet1/0/22
!
interface GigabitEthernet1/0/23
!
interface GigabitEthernet1/0/24
!
interface GigabitEthernet1/0/25
!
interface GigabitEthernet1/0/26
!
interface GigabitEthernet1/0/27
!
interface GigabitEthernet1/0/28
!
interface Vlan1
 ip address 192.168.200.245 255.255.255.0
!
interface Vlan2
 ip address 192.168.100.254 255.255.255.0
 no ip route-cache
!
ip default-gateway 192.168.100.1
ip http server
ip http secure-server
!
!
!
banner motd ^Cto #
Welco^C
!
line con 0
line vty 0 4
 password otgswitch
 login
line vty 5 15
 login
!
end

Please advise on what I might be doing wrong. Would appreciate your help.

0

I was facing problem due to loss of information in the dhcp binding table. In short the subscriber id automatically generated would not match my reservations. Here are some examples:

port#  interface  received SID(hex)      expected SID(hex) 
2      Gi1/0/2    0047-6931-2f30-2f      0047-6931-2f30-2f32 
13     Gi1/0/13   0047-6931-2f30-2f31    0047-6931-2f30-2f31-33 
24     Gi1/0/24   0047-6931-2f30-2f32    0047-6931-2f30-2f32-34 

I was hitting IOS bug present in some 15.0 releases. I updated my ios to 15.2 and problem solved!

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