There isn't a whole lot of info out there for this issue outside of a well done YouTube video by Christian McDonald and a few Comcast Community forum posts so I wanted to make sure people hear about this problem. We'd been having some problems with our Comcast service for a few days and the techs decided it would be a good idea to try a different modem. We had an older SMC gateway (SMCD3G) that has been a workhorse model for Comcast for a number of years now. We got the latest and greatest business gateway they had locally - a Netgear CG3000DCR.
Speeds were pretty good with it right away but that very same day we had a number of HTTP/HTTPS timeouts. That stuff happens so I wasn't too concerned but over the next couple of days it became an issue that was not going away. After some investigation we discovered 2 things - The most brief outages were simply HTTP timeouts that were inexplicable. The longer outages were happening because the modem would reboot itself from time to time.
Latency was also an issue. HTTP traffic would be fast for established connections but establishing a new connection was very slow. This was not the case for PCs connected to a public network we have for some public terminals. Internet there was lightning fast and new connections were very fast. Our setup was very similar to that YouTube video I linked to above - one firewall static IPs through the Netgear, the other firewall DHCP through the Netgear.
Firmware was the latest 1.32.03. Signal was good from Comcast and configuration was a direct copy from the old SMC gateway. Everything really pointed to the static IP problems others are complaining about with the Netgear. This morning a tech stopped by to put an SMCD3G back in. As soon as it was hooked up all our problems went away. Fast internet, low latency, no timeouts.
So beware the Netgear CG3000DCR for now. I think it's just fine if your firewall is configured with DHCP on the WAN. For those of you with static public IPs stick with the SMC gateways for now.