> OK, so I called Comcast and explained exactly the above about the > /29 routed to a /30 and the representative was clueless, so I asked > them to open up a ticket and escalate to a tier 2 tech. We shall see > what they say. > > This obviously means that they will create a new block of public > IP's for the /30 in addition to the 5 that I already have in the > /29. > > This seems easier to pay them for that then host and deal with more > equipment in my location.
Every inter-router link must have at least two IP addresses, one for each router. The smallest possible subnet in IPv4-over-ethernet that can contain two addresses is a /30. What did Comcast tell you to use as the subnet mask for your 5 addresses? If it's anything other 255.255.255.248, you don't have a /29 at all, you just have six individual IPs in a larger subnet that are allocated to you. I'll bet you're merely part of a much larger subnet. In fact, I would recommend just forgetting about the whole notion of using a router properly, with Comcast. (Anyone with differing experience - please let us all know how you managed to get them to do routed IP!) Most MSOs (cable operators) run extremely large subnets (my cable modem at home is running on a /22 subnet!) and use relatively strange L2 (bridging) features to make their networks work. And, speaking as an ISP operator, that does make sense for that kind of technology and the network design it mandates. It does complicate matters for you, however. The upside is that it's much cheaper for Comcast to do it that way than for a traditional ISP to allocate you a router port. This only rarely translates to cheaper service for you - it usually just translates to more profit for Comcast. -Adam Thompson [email protected] _______________________________________________ List mailing list [email protected] http://lists.pfsense.org/mailman/listinfo/list
