The portal of Nordlicht Reisen GmbH, a fictional travel agency, does not only fetch data, it also makes calls: payment providers, hotel chains and airlines accept calls only from addresses they know in advance. Anyone who leaves outbound traffic to chance has no answer to that. This lesson chooses the way out to the internet for Azure resources and sets the frame into which lessons 6.2 to 6.4 place their building blocks: the topology of the network.
Prior knowledge. Virtual networks, subnets and public addresses are set up in AZ-104, lesson 4.1; peering and routes, with a first look at hub and spokes, in AZ-104, lesson 4.2; the load balancer in AZ-104, lesson 4.6. How the Kladde slices its network is shown in K4, lesson 4.7.2, and the entry through Front Door in K3, lesson 3.3.4. None of this is repeated here. What is new is the choice: which way out for which requirement, and which topology carries the network. The connection to the data center follows in lesson 6.2, performance and security in lesson 6.3, the distribution of incoming requests in lesson 6.4.
The requirement
All numbers are assumptions of the exercise, not measured. Rows G-01 to G-10 from lesson 0.2 apply.
| No. | Requirement | Type | Metric | Weight | Source |
|---|---|---|---|---|---|
| 6.1-01 | The portal and the partner interface are reachable from the internet by name (G-02, G-05). | F | reachable under its own name; assumption | Must | Management |
| 6.1-02 | Calls to payment providers and hotel chains come from fixed, previously registered addresses. | R | at most 4 sender addresses; assumption | Must | Payment providers, hotel chains |
| 6.1-03 | Even at the load peak (G-09), outbound connections do not fail for lack of sender ports. | Q | up to ten times the normal load; assumption | Should | Sales |
| 6.1-04 | Servers have no public address of their own and cannot be reached directly from the internet. | R | 0 public addresses on servers; assumption | Must | Data protection |
| 6.1-05 | The network separates the portal, partner access and administration. | R | three separate environments; assumption | Should | Operations |
| 6.1-06 | A second region (module A3) may be added later without rebuilding the network. | Q | one more network range per region; assumption | Should | Management |
| 6.1-07 | The network stays operable for a team of two. | K | ranking: cost before operating comfort, not before availability (lesson 0.2) | Could | Management |