3

I am using packettracer to configure a network. The problem is that the router (that is acting as a router-on-a-stick) is not offering ip-addresses from its pool. The pc that act as the client belongs to vlan 30 and the interface fa0/1 on the switch is in acess-mode state. So no problem. And - the G0/1-interface to the router is configured as a trunk link. OK! AND - And the PC can communicate with ICMP-messages to the router if its configured static. So I do not understand why the router doesnt offer any address to the client?

When I click the DHCP-radiobutton on the pc-GUI I get the following error information:

DHCP failed. APIPA is being used

Router config for dhcp

HQ(config)#ip dhcp excluded-address 10.10.10.193 255.255.255.192
HQ(config)#ip dhcp pool LAN
HQ(dhcp-config)#network 10.10.10.192 255.255.255.192
HQ(dhcp-config)#default-router 10.10.10.193
HQ(dhcp-config)#end

And the addressing info looks like this for vlan-30 on the router:

G0/0.30   10.10.10.193   255.255.255.192

And my config on the router for this subinterface

HQ(config-subif)#encapsulation dot1q 30
HQ(config-subif)#ip address 10.10.10.193 255.255.255.192

I add a screenshot here so you easily can see the topology of the network.

Would be greatful if someone could see why the router wont offer the ip-addresses? May it have something to do with the native vlan that is VLAN 45?

cincerely

enter image description here

4

You've excluded all IP's available in the pool except for the network address:

HQ(dhcp-config)#network 10.10.10.192 255.255.255.192

indicates available IP addresses are 10.10.10.192 upto and including 10.10.10.255, and

HQ(config)#ip dhcp excluded-address 10.10.10.193 255.255.255.192

Indicates that except for 10.10.10.192 these addresses cannot be used. So fix that last statement so the DHCP server actually has some addresses it can assign.

| improve this answer | |
  • Thanks a lot - now I can see what I did wrong - I put the subnetmask in the exluded-syntax which is wrong. Thanks!!! – Björn Hallström Dec 7 '14 at 16:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.