Cisco 1751 obtaining IP address 1

[tyl3r32]

I believe I have an easy question. I have a Cisco 1751 router that I am currently using as a router-on-a-stick because I have only 1 Ethernet port and that has 4 sub interfaces on it. Currently, I have this in a little lab area with no access to an external network. I was trying to set this up to obtain an IP address automatically, so just to try it out, I unplugged my 2950 switch from the ethernet port on the router, plugged a cable from the router into the network where I currently gain access to internet from my PC. There is a DHCP server on the network, so I set the router up to obtain an IP through DHCP:

interface FastEthernet0/0
ip address dhcp
speed auto
!
interface FastEthernet0/0.2
encapsulation dot1Q 2 native
ip address 192.168.1.1 255.255.255.0
!
interface FastEthernet0/0.3
encapsulation dot1Q 3
ip address 192.168.168.254 255.255.255.0
!
interface FastEthernet0/0.4
encapsulation dot1Q 4
ip address 10.10.0.1 255.255.255.0
!
interface FastEthernet0/0.5
encapsulation dot1Q 5
ip address 10.10.1.1 255.255.255.0

However, after plugging into the network and waiting a while, the router doesn't obtain any IP address. What else do I need to know or what am I doing wrong?

Thanks!

 

[burtsbees]

You can't have an ip address on the main interface that is broken up into sub-interfaces that have IP addresses on them. I am not sure you can do the dhcp for the vlan ip addresses, but you might...not sure with router-on-a-stick though.
In order for the fa interface to get a dhcp ip address, you'll have to remove all sub-int commands.

Burt

 

[tyl3r32]

Thanks, Burt! I was wondering if that was my problem. I was hoping there was a way around that, but I guess not. And just so you know, you are not able to do DHCP for the vlan ip addresses...it's not an option for the sub-interfaces. Thanks for the help!