We have decommissioned 2 of our DNS servers. Unfortunately we have one network device that only points to these DNS servers and the settings cannot be modified. It was setup by a third party which no longer exists and passwords are unknown. The cost of changing this device is to high.
Is it possible to create a switch rule to intercept traffic from this device that is destined for the old DNS servers and forward it to a new server?
Or is there a better solution?
If the traffic from this device to the 2 DNS servers goes over a router you might use NAT to overwrite the destination IP address to a different one, thus effectively sending the traffic elsewhere. This is usually used for TCP server load balancing, but might be useful in your situation. Have a look at this guide: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_nat/configuration/15-sy/nat-15-sy-book/iadnat-addr-consv.html#GUID-D4F13BC2-3855-4E3B-AB03-1FC22B9FDEDC
Yes, you can do NAT on a Catalyst 6880-X, no problem. The only thing is that the traffic must be L3 routed, not L2 switched (so from one VLAN/IP network to another VLAN/IP network).
For more information about available features per platform / software version have a look at the Cisco Feature Navigator: http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp