newbie problem trunking vlans from 2950 switch to 2811 router

[notbroken]

I need to have 2 vlans on a 2950 switch. Then trunk those back to the fa0/1 port on a 2811 router. I have tried but I am missing something, suggestions?

switch config:
interface FastEthernet0/2
switchport trunk native vlan 10
switchport mode trunk
no ip address
!
interface FastEthernet0/5
switchport access vlan 10
no ip address
!
!
!
!
interface FastEthernet0/24
switchport access vlan 20
no ip address
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
interface Vlan10
description US
ip address 10.0.2.248 255.255.255.0
no ip route-cache
!
interface Vlan20
description THEM
no ip address
no ip route-cache
shutdown
!
ip default-gateway 10.0.2.254


router config:
interface FastEthernet0/1
no ip address
duplex auto
speed auto
!
interface FastEthernet0/1.10
description US
encapsulation dot1Q 10
ip address 10.0.2.254 255.255.255.0
!
interface FastEthernet0/1.20
description THEM
encapsulation dot1Q 20
ip address x.x.x.x 255.255.255.240


Thanks,
Andy

 

[KiscoKid]

Presumably the router is attached to port fa0/2 on the switch?

On the router, try the following:

interface FastEthernet0/1.10
encapsulation dot1Q 10 native

 

[chieftan]

If you want to use 802.1q trunking try some of the following config suggestions:

This is for the trunked ports:-

interface FastEthernet0/2
switchport trunk encapsulation dot1q
switchport trunk native vlan 10
switchport trunk allowed vlan 10,20,100
switchport mode trunk

If you do not stipulate what VLANs are allowed over the trunk then ALL VLANs are allowed by default.

For the ports that are not trunked:-

Interface FastEthernet 0/3
switchport mode access
switchport access vlan 10


Dont forget about Spanning tree if using multiple layer 2 devices. This can be assigned via VLAN.

 

[chieftan]

Apologies, as an add on, please remember that both ends of an 802.1q trunk MUST be identical. So if you manually set the speed and duplex at one end, you must do the same at the other.

 

[notbroken]

KiscoKid - That was it.

Thanks for the help

Andy