On Mon, Feb 23, 2015 at 7:02 AM, Eric Germann <ekgerm...@cctec.com> wrote:
> Currently engaged on a project where they’re building out a VPC > infrastructure for hosted applications. > > Users access apps in the VPC, not the other direction. > > The issue I'm trying to get around is the customers who need to connect > have multiple overlapping RFC1918 space (including overlapping what was > proposed for the VPC networks). Finding a hole that is big enough and not > in use by someone else is nearly impossible AND the customers could go > through mergers which make them renumber even more in to overlapping 1918 > space. > > Initially, I was looking at doing something like (example IP’s): > > > Customer A (172.28.0.0/24) <—> NAT to 100.127.0.0/28 <——> VPN to DC <——> > NAT from 100.64.0.0/18 <——> VPC Space (was 172.28.0.0/24) > > Classic overlapping subnets on both ends with allocations out of > 100.64.0.0/10 to NAT in both directions. Each sees the other end in > 100.64 space, but the mappings can get tricky and hard to keep track of > (especially if you’re not a network engineer). > > > In spitballing, the boat hasn’t sailed too far to say “Why not use > 100.64/10 in the VPC?” > > Then, the customer would be allocated a /28 or larger (depending on needs) > to NAT on their side and NAT it once. After that, no more NAT for the VPC > and it boils down to firewall rules. Their device needs to NAT outbound > before it fires it down the tunnel which pfSense and ASA’s appear to be > able to do. > > I prototyped this up over the weekend with multiple VPC’s in multiple > regions and it “appears” to work fine. > > From the operator community, what are the downsides? > > Customers are businesses on dedicated business services vs. consumer cable > modems (although there are a few on business class cable). Others are on > MPLS and I’m hashing that out. > > The only one I can see is if the customer has a service provider with > their external interface in 100.64 space. However, this approach would > have a more specific in that space so it should fire it down the tunnel for > their allocated customer block (/28) vs. their external side. > > Thoughts and thanks in advance. > > Eric > Wouldn't it be nice if Amazon supported IPv6 in VPC? I have disqualified several projects from using the "public cloud" and put them in the on-premise "private cloud" because Amazon is missing this key scaling feature -- ipv6. It is odd that Amazon, a company with scale deeply in its DNA, fails so hard on IPv6. I guess they have a lot of brittle technical debt they can't upgrade. I suggest you go with private cloud if possible. Or, you can double NAT non-unique IPv4 space. Regarding 100.64.0.0/10, despite what the RFCs may say, this space is just an augment of RFC1918 and i have already deployed it as such. CB
