Summary
hsd1.dc.comcast.net are subdomains to this hostname.
comcast.net is a domain controlled by three nameservers at
comcast.net themselves. All of them are on different IP networks. Incoming mail for
comcast.net is handled by eight mailservers also at
comcast.net. There are four duplicated IP numbers. Some of them are on the same IP network.
comcast.net has four IP numbers. Some of them are on the same IP network.