Question Support dynamically assigned IPv6 addresses on Plesk for Linux

[AYamshanov]

Hi everyone,

I am creating this post thread for discussing any questions about supporting dynamically assigned IPv6 addresses on Plesk for Linux and reporting any possible bugs.

As you may be already known, we have added possibility to enable the supporting of dynamic IPv6. It is not a production-ready feature yet, but you could test how it works exactly with your server environment on a test or a staging server.

Linux
[...]
* It is now possible to enable beta support for dynamic IP addresses by adding the following lines to the panel.ini file (not recommended for use in production, please report any issues you encounter on the Plesk Forum):

[network]
dynamic_ipv6 = on

[...]
(c) Change Log for Plesk Obsidian

Feel free to ask or reporting anything regarding the thread's topic!

 

[Hans | Pixel Creation]

Hi, I would love to get Dynamic IPv6 assignment working. However, I couldn't find any official documentation on the topic other than the announcement of the feature with the caveat of it not being production ready, as well as this post.

What is the current status of this feature? How does it work, exactly? Is this done, or still being developed? Is there a support article detailing instructions and the working of the feature I've missed or if it doesn't exist, could that be written?

 

[AYamshanov]

Hi! After the announcement of beta support in 2020, we have not found and not received information about critical issues from customers who started using dynamic IPv6 addresses. Since the start of summer 2021, the option is switched to "on" for supported Plesk Obsidian versions.

Now it should work out of the box; dynamic IPv6 addresses should be shown inside the Plesk Panel, it should be possible to choose them.

P.S. It is actual for Plesk for Linux because dynamic IPv6 addresses in Plesk for Windows are available for a long-long time... we have aligned Plesk for Linux and for Windows in this aspect.

 

[Hans | Pixel Creation]

This is not my experience.

What I expect is that you can have a domain be assigned an IPv6 address automatically or manually from a pool of available IPv6 addresses in the specified subnet.

The current reality is that you can only manually (not automatically!) assign the specific IPv6 addresses that are (manually) specified in the list of IP Addresses.

Please let me know what I'm missing and please consider that I'm not an IPv6 expert.

 

[Kaspar]

What I expect is that you can have a domain be assigned an IPv6 address automatically or manually from a pool of available IPv6 addresses in the specified subnet.

The current reality is that you can only manually (not automatically!) assign the specific IPv6 addresses that are (manually) specified in the list of IP Addresses.

First off I am also no expert on network or IPv6 topics. However it looks like there is some confusion about what "dynamically assigned IPv6 addresses" actually is. From my understanding it's a DHCP type of configuration for IPv6. Mostly used by large cloud providers who often do not use fixed IP addresses. (I might be wrong here. Like I said, I'm not a network expert).

It seems you're talking about a different feature regarding the use of IPv6. Mainly to have IPv6 addresses automatically assigned to subscriptions/websites in Plesk as is the case with IPv4 addresses. Unfortunately the automatic assignment of IPv6 addresses is not (yet) support by Plesk.

 

[Hans | Pixel Creation]

It seems you're talking about a different feature regarding the use of IPv6. Mainly to have IPv6 addresses automatically assigned to subscriptions/websites in Plesk as is the case with IPv4 addresses. Unfortunately the automatic assignment of IPv6 addresses is not (yet) support by Plesk.

This is only a minor annoyance that I wasn't referring to. My problem is this:

My VPS has an IPv6 /64 subnet assigned to it. This means I have a block of 18 quintillion IPv6 addresses at my disposal for just that VPS alone. Yet the only way—it seems—I am able to assign a new IPv6 address to a website is to manually create one through Tools & Settings → IP Addresses → Add IP Address. This does not scale.

What I would expect is a system where Plesk is able to automatically reserve a dedicated IPv6 address from within that subnet and assign it to a domain (and release it when the domain is removed). This would result in easily being able to set up each domain with their own unique IPv6 address.

As opposed to the current scenario where you take one specific IPv6 address from that subnet (most likely ::1) which is set as shared in Plesk and have every single site on the server share the same single IPv6 address which runs completely counter to the philosophy and utility of IPv6.

Please let me know if I'm misunderstanding any of this.

@AYamshanov Is this what the "supporting of dynamic IPv6" entails? If not, could you please explain as clearly as possible what the feature does?

 

[Kaspar]

Ah, I misunderstood your issue. Sorry about that. As far as I am aware of there is no option in Plesk to automatically assign IP addresses from an IP range (or pool). That would however certainly be a nice feature to have.

From my understanding "dynamic assigned IPv6" is an option for the network interface to use SLAAC (stateless address autoconfiguration). As opposed to having static addresses (or ranges) configured on a network interface. It can be configured by using IPV6_AUTOCONF="yes" in the network configuration of a server if, of course, the network (provider) supports SLAAC. The 'support' Plesk has for this is that it now can 'read' the IPv6 range if it's configured as dynamic on the network interface.

So, in short, it's support for a type of network configuration and has nothing to do with IP address distribution or assignment.

 

[Mark R]

Hi,
I have Plesk on IONOS and would like to create image backups, IONOS are warning of creating image backups if 'IPv6 address is assigned using DHCP'

Important Note--
When you create an image of a Linux server that is assigned an IPv6 address using DHCP, the server's IPv6 settings are also cloned. As a result, the antispoofing and firewall rules in the configuration are not automatically adjusted so that they are configured for the IPv6 address of the original server. Therefore, before creating an image from a Linux server that is assigned an IPv6 address, make sure that the leases file (e.g. /var/lib/dhclient/dhclient6-eth0.leases or /var/lib/dhclient/dhclient6.leases) is always removed.
This does not apply if the IPv6 address is statically assigned. In this case, no leases file will be created, so the IPv6 settings will not be cloned when creating an image.

I see there is a lease file in var/lib/dhcp/dhclient6.lease ..... is this the same file but a different path?

Can anyone confirm if IPv6 is dynamically created by default, if so any advice would be helpful

 

[Michael Pratt]

Yeah, I do not think the original post was meant in the way that Dynamically generated IPv6 addresses are supposed to be used. And MAY come from a fundamental misunderstanding of the entire reason around switching from IPv4 TO IPv6 in the first place.

TLDR version:
IPv4 does not have enough IP addresses in the pool to be able to have an IP address for every entity (every website, computer, home network, etc. much less all of the new devices that need to be able to communicate with the internet these days, phones, watches, TV's, light bulbs, etc.)

IPv6 came along so every possible thing on the internet (toasters, light switches, bulbs, AC coils, etc. could have their very own individually identifiable address on the internet (not just on a network).

Which would NOT make sense to use them on a server as we do currently with many websites belonging to a single IP address. They can have their own, and a server could literally never run out of them, even if the used ones never went back into the pool.

So when we are designated an entire block of IPv6 addresses, we just want a random one assigned to it from the pool of IP's. This is how the internet will ultimately work in the future when IPv6 eventually is forced to go live, and ideally it would already work like that on here.

So when a dynamic IPv6 address is talked about, this is likely what most people are thinking; that it can be used to dynamically generate IP addresses for domains/subscriptions from a pool

 

[Hans | Pixel Creation]

So when a dynamic IPv6 address is talked about, this is likely what most people are thinking; that it can be used to dynamically generate IP addresses for domains/subscriptions from a pool

Precisely this!