回複：Thanks. IP assigned by comcast changes

-- The IP address assigned by comcast changes over time. How to resove this?

Some of router support DDNS. Even your router does not support DDNS, for non-business usage , you can reset your external IP with dyndns.com if IP changes.

Currently, at least in some cites, Comcast issues static IP for resident Internet subscribers without additional charges. You can ask comcast. I got an static IP 2 months ago with regular account. For business, just pay $10 more for a static IP.