cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
708
Views
5
Helpful
3
Replies

L3 DHCP server problem?

thomas-renny
Level 1
Level 1

Hi,

I my office i have Cisco L3 switch C3560v2-24TS, also act as DHCP server.

some times when users try to connect to the network, DHCP server not assigning IP address to the clients (not everybody but some of the users).

Please help me to solve this issue. DHCP 1-199.

3 Replies 3

Hello
Can you post your config of the router

When you say it doesn't affect all users- is it the same users in the same area or different users every time?

Res

Paul

Sent from Cisco Technical Support iPad App


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

azzour_main#sh run

Building configuration...

Current configuration : 6675 bytes

!

version 12.2

no service pad

service timestamps debug uptime

service timestamps log datetime

no service password-encryption

service sequence-numbers

!

hostname azzour_main

!

boot-start-marker

boot-end-marker

!

enable password vkfkd!0901

!

no aaa new-model

system mtu routing 1500

ip subnet-zero

ip routing

no ip domain-lookup

no ip dhcp use vrf connected

ip dhcp excluded-address 172.23.47.201 172.23.47.254

!

ip dhcp pool GSdhcp

   network 172.23.47.0 255.255.255.0

   default-router 172.23.47.254

   dns-server 165.243.39.17 195.226.228.74

   lease 3

!

!

!

!

!

!

!

!

!

spanning-tree mode pvst

spanning-tree extend system-id

!

vlan internal allocation policy ascending

!

!

!

interface FastEthernet0/1

description Mail_M(249)

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/2

description Mail_B(248)

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/3

description VOIP#1(241)

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/4

description VOIP#2(242)

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/5

description Eworks_SVR

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/6

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/7

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/8

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/9

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/10

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/11

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/12

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/13

description L2_1

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/14

description L2_2

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/15

description L2_3

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/16

description L2_4

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/17

description L2_5(Training Room)

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/18

description UPS MGM

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/19

description File S/V

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/20

description # TMS Mgmt #

switchport access vlan 372

switchport mode access

speed 100

duplex full

!

interface FastEthernet0/21

switchport access vlan 372

switchport mode access

!

interface FastEthernet0/22

description # TMS Mirroring #

switchport access vlan 372

switchport mode access

speed 100

duplex full

!

interface FastEthernet0/23

description # Internet RTR #

switchport access vlan 372

switchport mode access

bandwidth 10240

!

interface FastEthernet0/24

description # Biz RTR #

switchport access vlan 372

switchport mode access

bandwidth 1024

!

interface GigabitEthernet0/1

!

interface GigabitEthernet0/2

!

interface Vlan1

no ip address

!

interface Vlan372

ip address 172.23.47.254 255.255.255.0

!

interface Vlan373

no ip address

!

ip classless

ip route 0.0.0.0 0.0.0.0 172.23.47.252 name Internet

*

*

*

*

!

snmp-server community infogs RO

!

control-plane

!

banner motd ^CCC

*******************************************************************

Access to this computer system and associated network, computer

resources, or data is restricted to those authorized by GS E&C. This

computer and related networks, resources or data may only be used

for business purposes of GS E&C and its customers.  Use by unauthor-

ized individual or for an unauthorized purpose is a violation of

LG CNS Security Policy. Violators will be prosecuted.

********************************************************************

^C

!

line con 0

line vty 0 4

password ******

login

line vty 5 15

password *********

login

!

!

end

Renny,

I do not want to intrude into Paul's line of answering but after a short review of your configuration, these are two my suggestions:

  • Lower the DHCP lease time from 3 days you currently have to something considerably shorter, say, 30 minutes. Use the lease 0 0 30 command in your DHCP pool to accomplish this. This will allow for quicker reuse of your IP addresses.
  • Try using the spanning-tree portfast default global configuration command to declare all access ports as PortFast ports by default. This will allow the station to obtain its IP address more rapidly, without needing to wait over 30 seconds after it is first connected to a port.

Best regards,

Peter