feat(vps): dns more info

Author: RoRoJ

network/vpc/reference-content/dns.mdx

@@ -1,9 +1,9 @@
 ---
 meta:
-  title: Understanding internal DNS
+  title: Understanding Scaleway DNS
   description: Learn more about how internal DNS works within the Scaleway ecosystem, and how to ensure your infrastructure is using DNS efficiently.
 content:
-  h1: Understanding internal DNS
+  h1: Understanding Scaleway DNS
   paragraph: Learn more about how internal DNS works within the Scaleway ecosystem, and how to ensure your infrastructure is using DNS efficiently.
 tags: vpc private-network dns dns-server dns-resolution hostname
 dates:
@@ -21,36 +21,49 @@ The **D**omain **N**ame **S**ystem (DNS) is a naming system for devices connecte
 
 ## Scaleway DNS overview
 
-Scaleway Private Networks benefit from managed internal DNS. This allows the resolution of resources' **hostnames** on the Private Network, into their private IP addresses. This managed DNS service is automatically exposed in each Private Network and no user-configuration is required.
+Scaleway Private Networks benefit from managed internal DNS. This allows the resolution of resources' **hostnames** on the Private Network, into their private IP addresses. This managed DNS service is automatically exposed in each Private Network and no user configuration is required.
 
 <Message type="note">
 When a Private Network is attached to a [legacy Public Gateway](/network/public-gateways/concepts/#ipam), the gateway’s DNS takes priority over that of the Private Network.
-<Message>
+</Message>
 
 ## Hostname format
 
-A resource's hostname is equivalent to the name you gave the resource when creating it. For example, if you have an Instance with the name `instance123` attached to a Private Network named `prodpn`, its address on that network is `instance123.prodpn.internal`.
+A resource's hostname is equivalent to the name you gave the resource when creating it. The full format for internal addressing is `<hostname>.<private-network-name>.internal`. For example, if you have an Instance with the name `instance123` attached to a Private Network named `prodpn`, its address on that network is `instance123.prodpn.internal`.
 
 <Message type="tip">
 - If you update the resource's name after creating it, and thus its hostname changes, it will not be automatically updated on our DNS records unless you detach and reattach the resource to the Private Network. <br/><br/>
 - If you created the resource via the API, and it has dots in its name, these dots should be replaced by dashes for the purposes of DNS resolution (`my.instance` --> `my-instance`). We generally recommend avoiding using dots in your resource names to avoid issues.<br/><br/>
-- You can also reach a resource via its resource ID, e.g. `e49902a6-ed4c-431f-bd62-0fc41063eec0.prodpn.internal`
-
+- You can also reach a resource via its resource ID, e.g. `e49902a6-ed4c-431f-bd62-0fc41063eec0.prodpn.internal` - see below for full details.
 </Message>
 
 ## DNS resolution details
 
-The managed DNS service is exposed on each Private Network through the following IP addresses:
+The managed DNS resolver service is exposed on each Private Network through the following IP addresses:
 
 - IPv4: `169.254.169.254`
 - IPv6: `fe80::200:22ff:fe05:ca1e`
 
-The DNS service parses packets' DNS messages, rewriting DNS queries from `<resource_name>.<private_network_name>` to `<resource_name>.<private_network_id>.<vpc_id>` to enable hostname resolution across Private Networks within a VPC. 
+The service resolves both regular public records, as well as internal VPC records
+
+<Message type="tip">
+The `.internal` at the end of internal addresses is important in enabling the resolver to distinguish between internal and external/public DNS. For this reason, you should always add `.internal` when addressing resources within your VPC.
+</Message>
+
+The DNS service resolves the following formats:
 
-DNS is then fully resolved via an upstream DNS resolver cluster.
+```
+<resource_name>.<private-network_name>.internal
+<resource_name>.<private-network_uuid>.internal
+<resource_uuid>.<private-network_uuid>.internal
+```
 
 Note that DNS cannot resolve or forward queries between different VPCs. It can only resolve hostnames for resources within the same VPC, though they may be on different Private Networks within that VPC.
 
+## Rate limiting
+
+Currently, DNS requests are rate-limited to 50 requests per second per resource. Watch this space as we work to be able to increase this limit to accommodate higher traffic volumes.
+
 ## Troubleshooting
 
 If you experience problems with DNS, try the following steps:
@@ -63,13 +76,4 @@ If you experience problems with DNS, try the following steps:
 
 4. **Check whether you are using Network Manager**: DNS does not work out of hte box for Linux distributions using Network Managed, such as **RockyLinux**. Find out how to resolve this problem [in our troubleshooting page](/network/vpc/troubleshooting/private-dns-dhcp-not-working/#distributions-running-network-manager)
 
-If you are still having problems reaching a resource attached to a Private Network via its hostname, [open a support ticket](https://console.scaleway.com/support).
-
-## Anything else?
-
-E.g.
-- Any other tips for effective hostnaming
-- Any options for manual configuration (configuring custom DNS names or domains within SCW internal DNS?)
-- Anything re: InterLink?
-- Any best practices to ensure efficient DNS resolution/avoid unnecessary requests?
-- Any info as to which resources can access internal DNS/access to DNS query logging?
+If you are still having problems reaching a resource attached to a Private Network via its hostname, [open a support ticket](https://console.scaleway.com/support).