VPS & Linux
VPS IPv6 setup: address, route, firewall and DNS checks
IPv6 setup on a VPS is a routing and security task as well as an address assignment. A working AAAA record needs the guest address, route/gateway, firewall, service listener, reverse-DNS expectations, and application behavior to agree.
Confirm the provider-assigned prefix and route
Use the exact IPv6 address/prefix and gateway model supplied for the VPS. Providers may route addresses differently from IPv4, so copying an IPv4 gateway pattern can fail even when the address itself looks valid.
Check the resulting route table and source address selection.
Apply firewall policy to IPv6 too
Services that were protected by an IPv4-only firewall can become unexpectedly public when they bind to ::. Mirror the intended exposure for SSH, web, databases, management ports, and application listeners across both families.
Test from an external IPv6-capable network. A local-gateway ping does not prove public reachability.
Publish AAAA only after the service works
A client may prefer IPv6 when a AAAA record exists. If the web server, TLS certificate, firewall, or route is broken on IPv6, publishing DNS can make a previously healthy hostname fail for some visitors.
Verify HTTP/HTTPS and any other public service by literal IPv6 and hostname before DNS rollout.
Decide reverse DNS and outbound-mail policy
Servers sending mail need aligned identity and reputation considerations. If usable IPv6 reverse DNS is unavailable, prefer the proven IPv4 outbound identity and prevent mail software from selecting IPv6 opportunistically.
- Use the provider routing model.
- Mirror firewall intent across families.
- Test service before AAAA publication.
- Plan reverse DNS for server identity.