I have the following scenario. Connected to a Cisco 3560 switch (fa0/9) is another Cisco switch (that is operating at layer 2). On the other side of that second switch is a firewall. I want to send traffic from my Cisco 3560 switch to a network behind the firewall. So, here was my plan:
int fa0/9
ip address 209.52.62.17 255.255.255.240
int vlan 50
ip add 209.52.62.18 255.255.255.240 secondary (there is already an address on this vlan and vlan 50 is the Internet vlan)
ip route 209.52.62.16 255.255.255.240 209.52.62.17 (There will be a device on the other side of the firewall that will have the IP 209.52.62.19/28).
However, when I try to add the ip address to int fa0/9, I get an error. Right now, the 3560 is operating at layer 2. I think that I need to issue the command: "ip routing" to put it in layer 3, then put the ip address on port fa0/9. However, I am concerned that I will mess up my production environment. Is there any other way of doing this? The "ip route 0.0.0.0 0.0.0.0" statement sends traffic out the gateway to the Internet. I just want to send packets to 209.52.62.16/28 out int fa0/9.
