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Problems to receive IPs address from DHCP server with multiple scopes

HI all !

End user has a WS-C3560G-48TS-S  with c3560-ipbase-mz.122-50.SE5 as switch CORE where intervlan routing is set.

A windows DHCP server with 3 scopes has been configured and is conected to port 8 in switch core.


At the beginning all user and server were in vlan 1 (172.16.30.X) then  end user requested to separate network segment;new vlan were set for  servers, user, wlans user. In windows DHCP server were defined new scopes for 172.16.33.X, 172.16.35.X


When I try to moved user to 17.16.33. X or 172.16.35.X ( previously the switch port are configured  in new vlan)they don´t get

ip address of new segment, some time  receive ip address (169.x.x.x) , other times the original segment 172.16.30.X.
just in few times  new segments are assigned correctly to ports.

My doubt is,

is there something left in switch's configuracion?
the switch's port where windows DHCP  server is connected required an special config?
maybe something wrong in configuration with windows DHCP server (I checked that new scopes are set and active)?

any suggestion for this issue?

thanks in advance for your help

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

ip routing

!
interface Vlan300
description  SERVER
ip address 172.16.30.30 255.255.255.0
ip helper-address 172.16.30.1
!

interface Vlan320
description Mgmt
ip address 172.16.32.254 255.255.255.0
!
interface Vlan330
description Users
ip address 172.16.33.253 255.255.255.0
ip helper-address 172.16.30.1

interface Vlan350
description WLAN_Users
ip address 172.16.35.253 255.255.255.0
ip helper-address 172.16.30.1

interface GigabitEthernet0/8
description SERVER DHCP
switchport mode access
switchport access vlan 300

interface GigabitEthernet0/X
description users
switchport mode access
switchport access vlan 330


interface GigabitEthernet0/X
description users
switchport mode access
switchport access vlan 350

21 Replies 21

Jon Marshall
Hall of Fame
Hall of Fame

Providing your DHCP server is 172.16.30.1 then there doesn't seem to be anything obviously wrong with your config. By the way you don't need an ip helper-address on the iinterface for vlan 300 because the DHCP server would see broadcasts from clients in that vlan anyway.

I would be looking at the DHCP server setup.

Edit - i'm assuming the new vlans were created at L2 as well ie. does a "sh vlan brief" show the new vlans ?

Jon

Hi Jon,

thanks for your quick response .

All vlans were created and are active ( in this info the new vlans are not associted to the switch's  port I shown previously, because a return to vlan 1)

Unfortunately I'm not specialist in windows server so I can't confirm if the config of multiple scopes is wrong or there is somethinng left. I just reviewed general config of the new scopes and that were active.

thanks for you tip for vlan 300

SW#sh vlan brief

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
300  Servidores                   active
310  VoIP                         active
320  Mgmt                         active
330  Users                        active
340  Reserva                          active
350  WLAN_Users                   active
1002 fddi-default                     act/unsup
1003 token-ring-default               act/unsup
1004 fddinet-default                  act/unsup
1005 trnet-default                    act/unsup
SW#

Thanks for the output.

I would pick a test PC, do an "ipconfig /release" on it and then allocate it into the new vlan and try an ipconfig /renew" . There is nothing else that you have configured on the switch that could be confusing the issue is there ?

Jon

Hi jon

I really appreciate your time.

We have alredy tried that option and others

ipconfig /release  then  ipconfig /renew

disconnect the cable

disable the interface and enable once again

reset the PC or lap

any of this works

regards

Okay, if you post the config we can check if there is anything there that could be causing the problem.

So you have -

1) ipconfig /release on PC. Check that PC has no IP.

2) on the switch allocate that PCs port into the new vlan

3) check that the L3 inertface for the new vlan is up/up (sh ip int brief | include Vlan)

4) ipconfig /renew on the PC

If you have done in it this order then please ignore.

Jon

Hi Filiberto,

I would go back to the servers guys and asked them if they have configured the scopes correctly with correct gateways?

Also, rebooting the server may help too.

HTH

Hi Reza,

the new scopes includes ip address of default gateways correctly

regards

sajid_m123
Level 1
Level 1

As some one has mentioned that you don't need "ip helper-address 172.16.30.1" under vlan 300, please take this line out. I assume clients are MS windows based then it should be the issue with the DHCP server. Make sure the "DCHP server"service is up and running on the server and proper scope is configured.

Thanks,

Hi sajid,

DHCP service is up and running, the original segment is assigned correctly the news ones no

regards

When you only had one vlan and scope what was the subnet and subnet mask for that scope ?

Edit - the scopes have been activated haven't they ?

Jon

Hi jon,

this is the config after setting L3 interfaces and before moving user to vlan 300 or 350

      

the original subnet is 172.16.30.X 255.255.255.0

regards

If this is still in your config 

ip default-gateway 172.16.30.249

can you remove it and add the following and then retest -

no ip default-gateway 172.16.30.249

ip route 0.0.0.0 0.0.0.0 172.16.30.249

Jon

Hi Jon

I have already tried static route  0.0.0.0 0.0.0.0 172.16.30.249.

During these days I was looking up in microsoft forum about this issue, I found many cases exactly like this, unfortunately

any of them said if they solved this issue, microsoft specialist state that is a problem from cisco side :-(.

regards

Have you done DHCP debugging on the switch when the PC tries to get an address ?

What OS is running on the client PCs ?

Jon

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