Can not ping from vlan A to vlan B (switch/router)

[mirnesc92]

Hey guys,

I have a Cisco Catalyst C3750-24TS Switch and a Cisco 891-W Router, and I am unable to communicate from one VLAN to another.

This is my first time configuring a switch and router so it is more than likely a rookie mistake. I've been stuck on this for two days now trying everything to get it work but just can't seem to wrap my head around whats causing the issue. I downloaded Cisco Packet Tracer and tried to replicate the same scenario below and was able to get HOST-PC-A to ping HOST-PC-B on a different VLAN but when I put it into practice with the equipment I have, it doesn't get the same results.

From what I understand, in order to establish communication between two VLANs on a switch (L2 device), I need a router (L3 device).. or a L3 switch and just enabling ip routing via CLI.

I've set up two VLANs on SW1 and associated two ports to each VLAN. Each VLAN has one HOST-PC connected to it. I have also designated port 23 (Fa1/0/23) to be the trunk port going to the router.

On the router I setup port 8 (fastEthernet 8) as the trunk port going to the switch. I then created two sub-interfaces 8.10 and 8.20. I set up DHCP for each sub-interface and created two excluded ip ranges, which works fine. Both PC receive the appropriate IP's from router, so I know there is communication between the switch and the router.

I posted as much details as I could find on the switch and router below to hopefully help narrow the problem down.

SWITCH: SW1

SW1#show vlan br 

http://pastebin.com/pTUKiiXY

SW1#show ip int br

http://pastebin.com/RGvvwRzN

SW1#show run

http://pastebin.com/rQ60jXmA

ROUTER : R1

R1#show vlans

http://pastebin.com/3WkkXwEi

R1#show ip int br

http://pastebin.com/vwfWYRHt

R1#sh ip route

http://pastebin.com/VdiJGVh4

R1#sh run

http://pastebin.com/zat57XXj

[Raja_D]

Cool... happy to hear that your problem is resolved.

Cheers... !!!

[Raja_D]

Execute the command "show ip dhcp binding" on the router and do share the output of it.

[Raja_D]

Hi,

Firstly the trunking encapsulation has to be enabled on both the sub-interfaces that is configured on the router. For the 2 different vlans to communicate you need to have a L3 switch or a router that has the capability to perform the routing. Enabled truking encapsulation on the 2 subinterfaces of the router as shown below:

int fa8.10

encapsulation dot1q 810

int fa8.20

encapsulation dot1q 820

Once after the sub-interfaces are configured with encapsulation, have the respective default gateway's configured on both the hosts connected to their respective vlan's. Once done you should be able to communicate between 2 hosts that are in different vlans as the routing now happens through the router on their associated sub-interfaces bonded to 2 different vlans, and the arp entries of both the hosts would be seen in the router also.

Try it and let me know..

Good luck!

[mirnesc92]

I think I am more confused now then when I started, lol.

[Sam Cole · Accepted solution]

Actually i would say its more than likely that the machines still have their firewalls on which will not allow ICMP by default. 

Try either turning them off or allowing ICMP through