Does Comcast employ network security practices in addition to the congestion management technique?
Yes. As described above, Comcast employs a number of practices to help prevent unwanted communications such as spam as well as protect the security of our customers and network. Comcast limits the number of login, SMTP, DNS, and DHCP transactions per second (at levels far above ‘normal’ rates) that customers can send to Comcast’s servers in order to protect them against Denial of Service (DoS) attacks. We do not disclose the exact rate limits in order to maintain the effectiveness of these measures, which ensure that these critical services are available for all of our customers. Relevant limitations regarding Comcast’s email servers can be found at http://customer.comcast.com/Pages/FAQViewer.aspx?Guid=2fcfc017-8dc5-4464-945c-fe5ec58d9d4d. In order to further protect our customers, Comcast blocks a limited number of ports that are commonly used to send spam, launch malicious attacks, or steal a customer’s information, for example. You can see a list of these ports and additional detail
