I'm working with a Cisco 2621 and NAT to map ip addresses to machines in my cluster. Starting yesterday, I noticed heavy packet loss (60% loss reported by ping) to one ip address mapped to three ports on the same machine. However, all of the other ip addresses were responding fine and I experienced no packet loss when pinging the same machine from within the cluster. This continued until today, when I reset the routes (deleted and re-added all three NAT entries). Now pings appear to report no packet loss.
I haven't modified my router configuration in months. Does anyone have any idea what may have happened? I'd like to prevent another occurrence of this in the future.