Ah, don’t even know where to start
So many wrongs here. Let’s try and untangle this.
First, you cannot have a dynamic IP with your DNS. Full stop.
There is a DDNS service to manage and update your DNS records with dynamic IPs but this is beyond this discussion.
You need to get a static IP. I cannot suggest anything as I don’t know your infra setup. Get a static IP from your ISP or “persist” one given to you by your cloud provider.
Yes, you need a domain name. Purchase one.
Once your domain name is yours, either keep it on your domain issuer DNS server or move it to the DNS servers of your choosing.
Add an A record to your domain and assign your static IP to the host you just created.
So if your domain is “mypool.xyz”, and you create an A record “coolnode” with your IP assigned to it, your pool will be accessible via “coolnode.mypool.xyz”.
If you decide to change your IP address, you’ll need to update your DNS record with the new IP. It takes around 4 hours for the DNS to propagate across the world (roughly).
It doesn’t matter where your pool is. DNS is propagated and synced across all DNS servers. You can register your DNS in Ukraine and you can still query an Australian DNS server to resolve your host.
Routing and DNS are completely different animals. DNS is just a global service to resolve your hostname to an IP address. Routing is the IP layer. Routing uses algorithms which are beyond this discussion.
You can ping Perth from Sydney and it will go through Japan. You cannot control this unless you are an ISP and control the edge routers.
All the above is irrelevant to you as a PO. Your pool can be contacted by any other pool in the world which can be located in Antarctica, and it can take an unpredictable route. It will take “the shortest path”. If going from Sydney to Perth via Tokyo is considered “the shortest path” by the routing algorithm, it will take that route.
On a separate note, please don’t try to use just Australian pools. It defeats the point of decentralisation.
Yes, response times do matter to win the height battle, but you also need to think about decentralisation.
Imagine, that Australia has only 10 pools, and they all talk only to each other. Then what? Who is gonna propagate the block across the puddle? Thinking that it will be someone else to talk to Germany - no me - is a bit selfish in my opinion. Just get enough peers in your topology randomly from everywhere.