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).

[M02@rt37]

Hello @bilalzaman369,

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