IP Routing Question on 3560 Switches


I have a network with two Cisco Catalyst 3560 switches ( standard image ) and am trying to setup routing between VLANs.

The two switches are connected via fibre and the fibre port is set as a dot1Q trunk ( all VLANs ).

There are a number of VLANs:

VLAN3 VLAN4 VLAN5 etc...

None of these are on the management VLAN.

VTP is up and running across the fibre link so the VLANs are replicating between switches.

When I enable IP routing I can get some semblence of routing going on between VLANs, but not others. For example, a client on VLAN3 can ping another client on VLAN4, but cannot ping a client on VLAN5. VLAN5 can be pinged via the diagnostics utility in the switch though. Another strange one is that an APC UPS connected to one switch can be pinged by IP address from the other switch, but tyring to access the web control panel using the same IP address fails.

When two 3560 switches are configured as above, does IP routing have to be enabled on both switches? If so, what IP addresses should be used for the VLANs?

I have tried using, say, as the IP address for VLAN3 ( on both switches ) but this doesn't seem to make sense.

Reply to
Loading thread data ...


You only need ip routing on one switch, and that switch should have a vlan interface with an ip address configured for each vlan. The gateway address on the client PCs should be the ip address on the vlan interface for their vlan. The second switch only needs to have all the vlans (no vlan interfaces required).


Rich wrote:

Reply to
Kyle Evans


Thanks for that, you nailed it in one!

I scrubbed the routing config from the second switch, adjusted a few client gateway settings and "badda-boom" - working fine.

-- Rich

Reply to

Truthfully, and if these are failover, you should turn up an IP address on each and run HSRP which will be the gateway. Might as well have layer 2 and 3 redundancy, particularly if any boxes have a connection to each switch. Would hate for you to lose the switch that controls layer 3, and have the other switch be a sitting duck.

Reply to

Thanks for the tip Trendkill, I wasn't aware of HSRP. Looks good.

Reply to

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.