All of the CFACT modems need to be switched to a different Verizon data plan to avoid excessive charges, and that is going to require changing their static IP addresses. I don't know exactly when this will happen, but the change was approved this morning. At worst, all the modems stop connecting until the DSM script restarts them, either in 15 minutes or with a reboot at 4 hours. More likely, the impact will be minimal. The modems should reconnect on their own, get assigned a new IP address, and the dynamic DNS update script will update the dyndns.org address for each DSM automatically. If you happen to have hardcoded the IP address somewhere, such as in a ssh config or browser bookmark, then it will need to be replaced with the DNS name, like cc-isfs.dyndns.org.
Nagios will tell us if any DSMs do not come back as expected.
This is a good time to remind everyone who connects to the DSMs to be careful about authentication. If ssh reports that a host key has changed, then it's entirely possible it's because the previous IP address for a DSM has been assigned to someone else's host, and it's not a good idea to start sending credentials to an unknown host. If you're ever not sure, one way to confirm a DSM's address is to first log in through the ssh tunnel, since only our DSMs are able to authenticate with eol-rt-data to create the tunnel port.
Gary Granger AUTHOR
Verizon completed the switch and did not need to change the IP addresses after all. This has been a drill.