Enable IPv6 connection to AWS instances

I was planning to create an AWS instance to host my new project - Signals Talk. I noticed AWS is going to charge for public IPv4 addresses. On AWS Lightsail, IPv4 instances will be $2-$4 more expensive than IPv6-only instances. I decided to try and get an IPv6-only instance working for my application.

IPv6 only networking type is only selectable for Operation System (OS) only blueprint. So I chose Ubuntu 22.04 LTS. Also note that browser-based SSH client is not available - that means I will have to SSH from my local laptop. There’s another note: “An IPv6-only instance cannot be the origin for a distribution”, which does not affect my application.

After the instance is running, I tried SSH from my local:

$ ssh -i [secret.pem] ubuntu@[ipv6_address]
... No route to host

“No route to host”!? I wondered what that means… I searched around and suspected something’s not quite right in my setup. I went to https://test-ipv6.com and voila - I do not have an IPv6 address!

The last green check says my DNS server appears to have IPv6 internet access, so then I looked into my router (TP-Link Archer A7) configuration - Indeed IPv6 was enabled but Internet Connection Type was not selected! So I selected Dynamic IP (SLAAC/DHCPv6), got an IPv6 address, and hit Save.

I tested again at https://test-ipv6.com, this time scoring 10/10!

I tested SSH again and connected successfully. Similar to IPv4 connections, adding the following configuration to ~/.ssh/config also works:

Host myinstance
Hostname [IPv6 Address]
User ubuntu
IdentityFile [secret.pem]

Now I can get on with installing my application on the IPv6-only instance. 🙂