DHCP Not Working

[pbiggs]

I’m having an issue with DHCP which is configured only lab router. I have configured the excluded addresses and scope etc. my layer 3 Cisco 3750 attached clients are unable to obtain an ip. Pinging and traces all work properly. I’ve even tried adding an ip helper address which didn’t work. Does anyone have an idea what I’m missing? Same subnet and vlan 1 on the switch as well. 

[Reza Sharifi]

Can you post "sh run" from the switch that is providing IPs?

HTH

[pbiggs]

Hi Reza!

Here is the show run:

TR-SW1#show run
Building configuration...

Current configuration : 2469 bytes
!
version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname TR-SW1
!
boot-start-marker
boot-end-marker
!
!
!
!
no aaa new-model
switch 1 provision ws-c3750-48ts
system mtu routing 1500
vtp domain Pete.com
vtp mode transparent
ip routing
no ip domain-lookup
ip domain-name Pete.com
ip name-server 8.8.8.8
!
!
!
!
!
!
!
!
!
spanning-tree mode rapid-pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
!
!
!
interface FastEthernet1/0/1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1
switchport mode trunk
!
interface FastEthernet1/0/2
!
interface FastEthernet1/0/3
!
interface FastEthernet1/0/4
!
interface FastEthernet1/0/5
!
interface FastEthernet1/0/6
!
interface FastEthernet1/0/7
!
interface FastEthernet1/0/8
!
interface FastEthernet1/0/9
!
interface FastEthernet1/0/10
!
interface FastEthernet1/0/11
!
interface FastEthernet1/0/12
!
interface FastEthernet1/0/13
!
interface FastEthernet1/0/14
!
interface FastEthernet1/0/15
!
interface FastEthernet1/0/16
!
interface FastEthernet1/0/17
!
interface FastEthernet1/0/18
!
interface FastEthernet1/0/19
!
interface FastEthernet1/0/20
!
interface FastEthernet1/0/21
!
interface FastEthernet1/0/22
!
interface FastEthernet1/0/23
!
interface FastEthernet1/0/24
!
interface FastEthernet1/0/25
!
interface FastEthernet1/0/26
!
interface FastEthernet1/0/27
!
interface FastEthernet1/0/28
!
interface FastEthernet1/0/29
!
interface FastEthernet1/0/30
!
interface FastEthernet1/0/31
!
interface FastEthernet1/0/32
!
interface FastEthernet1/0/33
!
interface FastEthernet1/0/34
!
interface FastEthernet1/0/35
!
interface FastEthernet1/0/36
!
interface FastEthernet1/0/37
!
interface FastEthernet1/0/38
!
interface FastEthernet1/0/39
!
interface FastEthernet1/0/40
!
interface FastEthernet1/0/41
!
interface FastEthernet1/0/42
!
interface FastEthernet1/0/43
!
interface FastEthernet1/0/44
!
interface FastEthernet1/0/45
!
interface FastEthernet1/0/46
!
interface FastEthernet1/0/47
!
interface FastEthernet1/0/48
!
interface GigabitEthernet1/0/1
!
interface GigabitEthernet1/0/2
!
interface GigabitEthernet1/0/3
!
interface GigabitEthernet1/0/4
!
interface Vlan1
ip address 10.16.0.254 255.255.255.0
ip helper-address 10.16.0.1
!
ip default-gateway 10.16.0.1
ip classless
ip route 0.0.0.0 0.0.0.0 10.16.0.1
ip http server
ip http secure-server
!
!
!
!
!
line con 0
line vty 5 15
!
end

[Reza Sharifi]

Hi,

So, where is the DHCP scope configured? I don't see any DHCP config on this switch.

https://www.computernetworkingnotes.com/ccna-study-guide/how-to-configure-dhcp-server-on-cisco-switches.html

If the switch is working as a layer-2, you just need a default gateway command and can delete the ip route command:

ip default-gateway 10.16.0.1
ip classless
no ip route 0.0.0.0 0.0.0.0 10.16.0.1

HTH

[pbiggs]

Hi,

I have configured the DHCP Scope on the router. I tried all the commands thinking they might help. Here is the DHCP output from the routers show run:

TR-R1#show run | Sec dhcp
no service dhcp
ip dhcp excluded-address 10.16.0.1 10.16.0.20
ip dhcp pool DHCP-POOL
network 10.16.0.0 255.255.255.0
default-router 10.16.0.1
dns-server 8.8.8.8 4.2.2.2

I wanted the router to handle assigning the DHCP addresses to the clients. I had already configured and tested DHCP to be working for the clients if I configure on the switch itself. 

[Reza Sharifi]

The scope looks correct.

Can you remove 

no service dhcp

and try again?

HTH

[pbiggs]

how do I remove that? It was just added. What command is it to remove? would it be

conf t

no no service dhcp?

[Reza Sharifi · Accepted solution]

try:

service dhcp

HTH

[pbiggs]

Worked!! Thank you Reza!! You figured it out! Been Messing with this for a couple of days. Thank you once again. 

[Reza Sharifi]

Glad to help.

Good Luck!

Reza