users unable to reach DHCP from 6509 switch

[mahesh18]

hi all,

On 6509  switch from  one of modules users are unable to reach the DHCP  server.
This is user access switch.

Users from other modules on USer access switch are able to reach DHCP

Thanks

mahesh

[Giorgio Romano]

Hi,

are the users connected to the same module able to ping each others?

May you post a configuration of the 6509?

Try to enter the "show module" command on the 6509. With this command you should be able to understand if the module has any problem.

   giorgio

[IAN WHITMORE]

Are the user in this module on a different vlan?

Is the vlan allowed on the trunk?

Are you using IP helper address?

There could be many things to look for including a problem with the module itself as Giogio says.

We need more info.

Regards,

Ian

[mahesh18]

Hi Ian,

Thanks for reply.

Users are on diff vlan.

yes vlan is allowed  on trunk and it goes to distribution switch.

Distribution switch has IP helper address.

mahesh

[IAN WHITMORE]

If you have time, try the troubleshooting section of this guide:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a00800f0804.shtml

It has debugs and stuff to try and pinpoint the problem.

Could be an ACL. Not for the broadcasr because with help address you are converting the broadcast to unicast. But you might be blocking something somewhere.

HTH,

Ian

[mahesh18]

Hi,

Thanks for reply.

module has no issues

i run the sh diagnostic command it is fine,

also sh module  shows it ok.

Also i am able to ping the vlan IP  and its gateway from user access switch fine.

[IAN WHITMORE]

OK. So if you put a static IP can you even ping the DHCP server? You should be able to else there is either a routing problem or ACL. If a user can ping the gateway (distribution switch) they should also be able to ping the DHCP IP.

Another question. Might be silly. Are there enough IPs free in the DHCP pool on the server?

Regards,

Ian

[mahesh18]

Hi Ian,

IF we assign static IP  to user PC  and Default gateway and if that works then we can say that network is fine right ???

thanks

mahesh

[IAN WHITMORE]

You can say that the routing is right, but maybe not the configuration. Latchum has some good ideas in his post. Check those things out too.

Regards,

Ian

[Latchum Naidu]

Hi Mahehs,

Verify that the port has STP portfast enabled and trunking/channeling disabled. The default configuration is STP portfast disabled and trunking/channeling auto, if applicable.

And also verify that the ip helper-address command is located on the correct interface. The ip helper-address command must be present on the inbound interface of the DHCP client workstations and must be directed to the correct DHCP server.

Hope this helps you.

Please rate the helpfull posts.

Regards,
Naidu.

[mahesh18]

Hi naidu,

IP helper address  is config  on distribution switch.

thanks

mahesh

[lalarajaraman1985 · Accepted solution]

Mahesh,

  I would suggest you  check the configuration in DHCP server for the particular vlan, reason being there is no issues with switch end. IS the same vlan when configured in different switch is it working?

Regards

Raja

[mahesh18]

Hi,

Thanks for reply.

We assign static ip address  to user pc  and it got ip address and is working fine.

so this rules out network and DHCP server  has to be checked for vlan 13 config right??

mahesh

[mahesh18]

Hi ,

Many thanks all.

issue was with DHCP server as it was now showing up vlan 13 on its database.

thanks

mahesh