To whom it may concern,
Aside from the issues Comcast is having in my clients area I have a few quick questions.
1. I don't have this modem, so I can't walk you through the steps, sorry. In general, I always tend to recommend using your own router if you have any remotely sophisticated networking needs - these leased gateways are usually only good for the basics. As well, I have noticed that firmware updates (which Comcast does automatically, without notice) tend to reset some or even ALL of the settings on the gateway periodically.
2. You cannot view any logs. The SMC & Netgear gateways are not advanced enough to allow this capability. The Cisco gateways I believe do allow you to view logs.
Perhaps someone can chime in on the necessary port forwarding steps.