Ip addresses may not be configured on l2 links

[bilalzaman369]

My cisco router 881 when i assign the ip on fastethernet lan port then error will occured ip address may not be configured on l2 links can anyone give me solution please 

[Flavio Miranda]

Hi @bilalzaman369 

You need to get inside the fastethernet  interface  and run the command "no switchport"

[MHM Cisco World]

WAN interface can config with IP 
for LAN you can not config IP directly but you can assign to VLAN SVI assign to L2 port. 

[Richard Burts]

Your 881 router treats the  fastethernet lan port like it was a layer 2 switch port. And logically you can not assign a layer 3 address directly on a layer 2 port. I am not clear if the 881 supports it, but the suggestion from @Flavio Miranda about using no switchport would be one way to get a layer 3 address on the port. Otherwise I believe that the suggestion from @MHM Cisco World about configuring an IP address on the vlan interface associated with the lan port would be the way to go.

What will be connected to this lan port? Will it need a unique IP subnet for this port, or could it be one of several devices in the same subnet?

[Joseph W. Doherty]

I recall, as both @MHM Cisco World and @Richard Burts describe, to assign an IP to a FE LAN port, on the ISR 800s, you need to use a SVI.  If you intent is to only have one IP per L2 port, you assign just one L2 port to a specific VLAN, which has a SVI.

Some additional things to keep in mind.  First, I also recall some VLAN management/configuration, for an ISR 800's L2 ports, is just slightly different from other Cisco L3 switches, and second, 88x series routers are rated at about 50 Mbps throughput capacity (i.e. they are not intended for wirespeed LAN routing using FE ports).

[mr-pickles150]

Paso 1: Crear y configurar la VLAN

1. Crea la VLAN:

   Router(config)#vlan 10

   Router(config-vlan)#name SERVIDOR_VLAN

2. Configura la interfaz VLAN (SVI):

   Router(config)#interface fastEthernet0

   Router(config-if)#switchport mode access

   Router(config-if)#switchport access vlan 10

Paso 3: Configurar NAT (Network Address Translation)

Configura NAT para que el tráfico de la VLAN 10 tenga acceso a Internet a través de la puerta de enlace 192.168.1.1:

Router(config)#interface vlan 10

Router(config-if)#ip nat inside

Router(config-if)#exit

1. Configura la interfaz FastEthernet4 (WAN) para NAT:

   Router(config)#interface fastEthernet4

   Router(config-if)#ip nat outside

   Router(config-if)#exit

2. Configura la sobrecarga NAT para traducir las direcciones IP:

   Router(config)#access-list 1 permit 192.168.2.0 0.0.0.255

   Router(config)#ip nat inside source list 1 interface fastEthernet4 overload

[M02@rt37]

Hello @bilalzaman369,

Do you try no swirchport command on interfaces? After that, enter ip address command.

[Wizard4777]

you either create a SVI and assign IP or use no switchport command and assign IP. with no switchport command, VLANs cannot be passed as this will be a directly connected interface