IPv4 and IPv6 addresses on your CR Servers service

Every CR Servers service is reachable over IPv4 and IPv6 at the same time (dual-stack). Your service keeps its IPv4 address; IPv6 is added at no extra cost.

What IPv4 and IPv6 are

An IP address is the number other computers use to reach your server on the internet.

• IPv4 is the original addressing system, written as four numbers such as 203.0.113.10. The world ran out of new IPv4 addresses years ago, so each one is scarce and shared infrastructure often sits behind address translation (NAT).
• IPv6 is the current standard, written in hexadecimal groups such as 2001:db8:1234::10. There are enough addresses for every device to have its own, so there is no NAT and connections are direct from end to end.

Modern phones, home connections and mobile networks increasingly prefer IPv6 when it is available. Offering both means your site or server is reachable the fastest way for every visitor, and that nothing breaks for networks that are still IPv4 only.

What each service includes

Service	IPv4	IPv6 included	On request
Web hosting	Shared address of the hosting server, or a dedicated IPv4 as an add-on	Your own /64 block, assigned automatically	—
VPS	One dedicated IPv4	One IPv6 address assigned with the server	A dedicated /64 block
Dedicated server	Your assigned IPv4 addresses	One IPv6 address for the server's uplink	A routed /56 block
Colocation	Your assigned IPv4 addresses	One IPv6 address for your firewall's WAN interface	A routed /56 block

Web hosting

Each hosting account receives its own IPv6 /64 block, assigned automatically from the hosting server's pool. There is nothing to configure: the web hosting control panel publishes the IPv6 (AAAA) records for your domains alongside the IPv4 (A) records when your domain uses our name servers. If you manage DNS elsewhere, add an AAAA record with the address shown in the panel.

If your account does not show an IPv6 address yet, open a ticket and we will enable it.

VPS

Every VPS is delivered with one IPv6 address together with its IPv4 address. Both appear on your VPS page in the client area, with the prefix length and gateway you need if you ever reconfigure the network yourself. See Manage your VPS from the client area.

Our provisioning configures the addresses on first boot, so a freshly ordered or rebuilt VPS is reachable over IPv6 without any manual steps. If you install your own operating system image, or your image does not apply network settings on first boot, configure the address, prefix length and gateway shown in the client area as static settings.

If you need more than one address (for example one per site or per container), we can reserve a dedicated /64 block for your VPS. Request it by ticket.

Dedicated servers and colocation

We assign an IPv6 address on our network to your server's uplink, or to the WAN interface of your firewall if you run one. Support provides the address, prefix length and gateway when the service is delivered, or by ticket for existing services.

If you run your own firewall or router and want IPv6 on the networks behind it, we route a /56 block to you on request. The block is delivered through your WAN address: our network sends all traffic for the /56 to that address, and you split it into /64 networks for your internal segments. You are responsible for configuring and filtering the block on your own equipment.

How to check that IPv6 works

From a computer or network with IPv6 connectivity:

ping6 your-domain.com

On Windows use ping -6 your-domain.com. To test only the IPv6 path from a browser, open http://[your-ipv6-address]/ with the address in square brackets, or use a public checker such as test-ipv6.com from the server itself.

To confirm your DNS publishes an IPv6 address:

dig AAAA your-domain.com +short

If the ping or page works over IPv4 but not over IPv6, check the points below before opening a ticket.

Common pitfalls

• Do not block ICMPv6. IPv6 depends on ICMPv6 for neighbor discovery and path MTU discovery. A firewall that drops ICMPv6 makes connections hang or fail intermittently. Allow ICMPv6 at least from and to your own addresses and gateway.
• IPv6 firewall rules are separate. On Linux, iptables rules do not apply to IPv6; use ip6tables or nftables, or a tool such as ufw or firewalld that manages both. Windows Firewall has separate IPv6 rules. If port 80 or 443 is open for IPv4 only, the site is unreachable over IPv6.
• Services must listen on IPv6. Web, mail and database servers need to bind to the IPv6 address or to :: (all addresses). A published AAAA record for a service that is not listening makes clients wait before falling back to IPv4, so the site feels slow.
• Publish DNS only when it works. Test the address first, then add the AAAA record. Hosting accounts do not need this step: the panel publishes the record once the address is active.
• Reverse DNS for mail servers. Receiving mail systems check that the sending IPv6 address has a PTR record that matches your mail hostname. We set it for you on request: open a ticket with the address and the hostname, the same way as for a dedicated IPv4.

Frequently asked questions

Does IPv6 cost extra?

No. The address or block described above is included with every service. A dedicated /64 for a VPS and a routed /56 for a dedicated server or colocation are also free; request them by ticket.

Can I get more addresses?

Yes. IPv6 blocks are available as described above at no cost. Additional IPv4 addresses are scarce and are assigned with a justification, for example a dedicated IP for hosting or a separate mail service; ask by ticket and we will tell you what is available for your service.

How do I request a /64 or a /56?

Open a ticket from the client area, name the service, and tell us how you plan to use the block. We assign it, route it, and reply with the addresses and gateway to configure.

What if my application does not support IPv6?

Nothing changes for you. Your IPv4 address stays, and visitors on IPv4-only networks keep reaching you as before. You can leave IPv6 unused until your application is ready.