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Dhcp doesn't work with vlan more than 100

fooz843011
Level 1
Level 1

 i have a stackable 3750 L3 switch working as a core switch, when i create vlan  more than vlan 100 and configure a dhcp for this vlan 

dhcp is not working 

for vlan less than vlan 100 every thing is ok  and dhcp is working  

i dont know why 

is it according to version or liscence or what

for example :- creating van less than 100

vlan 90

name comp

int vlan 90

ip add 192.168.90.5 255.255.255.0

ip dhcp pool comp

network 192.168.50.0 255.255.255.0

dns-server 192.168.12.12

default-router 192.168.90.5

int g3/0/1

no sh

switchport mode access

switchport access vlan 90

spanning-tree portfast

and i connect any device laptop or any device to g3/0/1

dhcp   is working

  

every thing is ok about working of dhcp with all vlan with no. less than 100 but if i use any vlan no. more than 100 ,dhcp is not working but static address with it working

any one can help me

1 Accepted Solution

Accepted Solutions

Julio E. Moisa
VIP Alumni
VIP Alumni

Hi

I dont understand the question clearly, please correct me, if you create the vlan 100 and also create a new scope for that vlan, the dhcp will not work, right?

ip dhcp pool comp

network 192.168.50.0 255.255.255.0    <-- Network and default router must be on the same network segment. 

dns-server 192.168.12.12

default-router 192.168.90.5




>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

View solution in original post

7 Replies 7

Julio E. Moisa
VIP Alumni
VIP Alumni

Hi

I dont understand the question clearly, please correct me, if you create the vlan 100 and also create a new scope for that vlan, the dhcp will not work, right?

ip dhcp pool comp

network 192.168.50.0 255.255.255.0    <-- Network and default router must be on the same network segment. 

dns-server 192.168.12.12

default-router 192.168.90.5




>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

first sorry all vlan 90 not 50

 the problem is 

when u create a vlan less than 100 and configure a dhcp for that vlan 

it is working properly

if the vlan no. not the address more than 100 configure dhcp is not working 

l3 switch doesn't distribute any addresses using dhcp for that vlan

No worries my friend,

Ok if you create the vlan 100, for example:

vlan 100
name TESTING

interface fa0/20
switchport access vlan 100
switchport mode access
no shutdown

interface vlan 100
no shutdown
ip add 192.168.100.1 255.255.255.0

ip dhcp pool VLAN100
network 192.168.100.0 255.255.255.0
default-router 192.168.100.1
dns-server 8.8.8.8 4.4.4.4

ip dhcp excluded-address 192.168.100.1 

This configuration does not work for you, right? Have you configured the excluded-address?




>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

for vlan no. more than 100 dhcp doesn't work

for vlan no. less than 100 dhcp is ok and working properly

thank you,

That not make sense, please try my configuration otherwise it could be a bug. 




>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

yes correct

no excluded address