The firewall on my RVS4000 appears to hang when ever I use Netflix. If I disable the firewall and re-enable it it works for a while and then stops again. My IP address is in the Approved Client IP Addresses so it is excluded from the URL filtering and Web reputation rules.
I had the same or similar problem starting Friday. It was also occurring with Hulu Plus. (My streaming device is a Samsung Blueray Player). In addition to streaming problems, whatever was going on also caused the device to produce strange error messages that all went away when I unbridged my DSL Modem and started using it as the router. I have been slowly reconnecting everything today and now the RSV4000 appears to be working again. Was this possibly some kind of programming error by the enginners at Hulu and/or Netflix or some kind of internet attack aimed at streamng devices?
I contacted Cisco Small Business Tech support on my version of this problem and what appears to have resolved the problem for me was to change the DNS server(s) from my ISP's default to the google servers at 220.127.116.11 and 18.104.22.168 (you can do that in the LAN section of the setup tab in the configuration interface). Disabling the ISP function didn't appear to have any effect.
I still suspect that Samsung's (or Netflix and Hulu's) engineers may have been up to no good or there was some kind of DOS or DDOS attack on their services over the weekend.