How can I define a rate limit to a specifc IP address?
My version is 12.3(21) of IOS software.
The "rate-limit" command on IOS routers is fairly old, maybe you will be able to use it.
You can define an access-list to do rate-limiting to a specific ip address:
access-list 100 permit ip any host 10.1.1.1
rate-limit output access-group 100 150000 3000 3000 conform-action transmit exceed-action drop
This configuration means that you will limit the traffic to host 10.1.1.1 to 150 kbps.
Numbers "3000" are the committed burst and excess-burst values.
In case the traffic traverses a provider cloud, you will need to ask your provider about these values.