As YLearn points out, you need to determine if the switch is operating as strictly a layer-2 switch, or is it actually routing (layer-3). If it is routing, then you do not want to use the `default-gateway` or `default-network` commands.

You should not use the `ip default-gateway` commands on a router that is acting as a router, and the `ip default-network` command is really for IGRP, which doesn't understand the default route; you can use a static default route.

Cisco has a document that explains the differences: [*Configuring a Gateway of Last Resort Using IP Commands*][1].

You also say that the `10.6.9.10` address that you want to use for the gateway is another switch. You need to make sure that address really is a gateway for that network. Do not confuse the layer-2 LAN with the layer-3 routing. The address you use as a gateway needs to be a router (or layer-3 switch) that knows how to get to other networks.

You should edit your question to include a good description (a diagram would be great) of how your network is connected, and the full switch configurations. That would help us give you a more specific answer.


  [1]: http://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/16448-default.html