Cannot ping from Swith to Router but i can other way another

[flashGC88]

Hello Everyone,

I'm having a problem while configuring the router and switch and i don't know what the problem is. What i want to do it that i want to ping from the switch(Multi Layer switch) to the router but it doesn't work although i can do it other way around, can some please help me how i can fix this problem? thank you very much

[paul driver]

Duplicate post

https://supportforums.cisco.com/discussion/12760016/cannot-ping-swith-router-i-can-other-way-another

[Mark]

Hi flash,

I see you want to setup router-on-a-stick deployment. You need to remove the IP address of the router interface connected to the switch:

interface FastEthernet0/1
 ip address 172.18.1.1 255.255.255.0
 duplex auto
 speed auto

and also, you need to configure the switch interface connected to the router as trunk port.

Thank you,

Mark

[Mark Malone]

Hey
just quick couple of things on router

should be no ip address under physical interface of trunk link to layer 2 switch, only ips on sub-ints
interface FastEthernet0/1
 ip address 172.18.1.1 255.255.255.0

also no requirement for a router pointing back to switch , you should have router pointing outbound to say inetrnet
ip route 0.0.0.0 0.0.0.0 wan ip address

On switch side only 1 of the interfaces needs to be a trunk so just pick 1 and set as

interface FastEthernet0/24
 switchport trunk allowed vlan 2,3,8
 switchport trunk encapsulation dot1q
 switchport mode trunk

also should only be 1 vlan oin the layer 2 switch with an actual reachable SVI interface thats the point of the sub-ints on router side
and if its vlan 1 your leaving up then use this ip default-gateway 172.18.1.1 and get rid of the ip route its layer 3 command

this may help as its the design your tyrying to achieve will show you step by step
http://www.firewall.cx/cisco-technical-knowledgebase/cisco-routers/336-cisco-router-8021q-router-stick.html