Bug 2210710 (ipv6-mostly)

Summary:	[RFE] Support ipv6-mostly networks
Product:	[Fedora] Fedora	Reporter:	Petr Menšík <pemensik>
Component:	distribution	Assignee:	Aoife Moloney <amoloney>
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	rawhide	CC:	dominik, kevin
Target Milestone:	---	Keywords:	RFE
Target Release:	---	Flags:	blc: mirror-
Hardware:	Unspecified
OS:	Linux
URL:	https://ripe85.ripe.net/archives/video/923/
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2208386, 2210713, 2210721, 2212331, 2210722, 2212357
Bug Blocks:

Description Petr Menšík 2023-05-29 08:53:45 UTC

If the network provides IPv6, be able to use that. That is already supported. However, if the network requests its clients to use IPv6 only, do not allocate IPv4 address even if the network can provide it. Instead deploy legacy 464xlat connection if the network provides enough information for it. That allows most of applications to use IPv6 only, but have working fallback for applications using IPv4 fixed addresses.

Reproducible: Always

Steps to Reproduce:
1. Have a network providing both ipv6-only dhcp option and DNS64 announced ranges.
2. Connect to network
3. Have only IPv6 address allocated on network interface, IPv4 only on conditionally configured legacy interface.



Presentation on RIPE65 about IPv6 mostly networks:
https://ripe85.ripe.net/presentations/9-RIPE85-Deploying_IPv6_mostly.pdf
https://ripe85.ripe.net/archives/video/923/

Most of changes would need to be done on Network Manager probably. Other components might be involved too, therefore creating it on distribution.

Comment 1 Petr Menšík 2023-05-29 10:14:34 UTC

Interesting discussion for Microsoft's systems, found at PREF64 RA option discussion:
https://blog.apnic.net/2017/01/19/ipv6-only-at-microsoft/

There were also CSNOG presentation in Czech, given by the same presenter:
https://indico.csnog.eu/event/13/contributions/121/

Comment 2 Petr Menšík 2023-05-29 10:19:17 UTC

It seems to me this feature might be interesting also for virtual machine providers, where they could deploy services on many machines connected by IPv6 only connections, while allowing IPv4 connectivity to work for them.

Comment 3 Petr Menšík 2023-05-29 12:36:45 UTC

Useful references:

- NAT64: https://www.rfc-editor.org/rfc/rfc6146
- DNS64: https://www.rfc-editor.org/rfc/rfc6147
- 464xlat: https://www.rfc-editor.org/rfc/rfc6877
- DNS64 prefix discovery: https://www.rfc-editor.org/rfc/rfc7050
- ipv6-only: https://www.rfc-editor.org/rfc/rfc8925
- Happy Eyeballs v2: https://www.rfc-editor.org/rfc/rfc8305