Bug 2055322

Summary:	doesn't use ipv6 by default
Product:	[Fedora] Fedora	Reporter:	Brian J. Murrell <brian>
Component:	nfs-utils	Assignee:	Steve Dickson <steved>
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	38	CC:	bfields, luk.claes, steved
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
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Last Closed:	2023-07-20 17:10:04 UTC	Type:	Bug
Regression:	---	Mount Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Brian J. Murrell 2022-02-16 17:15:37 UTC

Description of problem:
Mounting an NFS share doesn't happen using IPv6 in the default mount scenario where the server is dual-stacked.

Version-Release number of selected component (if applicable):
nfs-utils-2.5.4-2.rc3.fc35.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Export a share on an dual-stack NFS server
2. Mount using a basic mount command "mount server:/src /mnt/tmp"

Actual results:
Export is mounted using IPv4

Expected results:
In this world, these days, IPv6 should be preferred over IPv4 if it's available.  It's how just about every other networking tool on Linux operates.

Additional info:
$ showmount -e server
Export list for server:
/src                  fd31:aeb1:48df::/64,10.75.22.0/24
$ host server
server.example.com has address 10.75.22.247
server.example.com has IPv6 address fd31:aeb1:48df::2
$ sudo mount server:/src /mnt/tmp
$ grep nfs /proc/mounts 
nfsd /proc/fs/nfsd nfsd rw,relatime 0 0
sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0
10.75.22.247:/src /mnt/tmp nfs4 rw,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=10.75.22.1,local_lock=none,addr=10.75.22.247 0 0
$ sudo umount /mnt/tmp
$ sudo mount -o mountproto=tcp6 server:/src /mnt/tmp
$ grep nfs /proc/mounts 
nfsd /proc/fs/nfsd nfsd rw,relatime 0 0
sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0
server:/src /mnt/tmp nfs rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp6,timeo=600,retrans=2,sec=sys,mountaddr=fd31:aeb1:48df::2,mountvers=3,mountport=20048,mountproto=tcp6,local_lock=none,addr=fd31:aeb1:48df::2 0 0

IMHO, the behaviour of the first mount command there should have had the same result as the second one, that forced the use of IPv6.

Comment 1 Ben Cotton 2022-11-29 17:54:21 UTC

This message is a reminder that Fedora Linux 35 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 35 on 2022-12-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '35'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, change the 'version' 
to a later Fedora Linux version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora Linux 35 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora Linux, you are encouraged to change the 'version' to a later version
prior to this bug being closed.

Comment 2 Ben Cotton 2023-02-07 14:52:53 UTC

This bug appears to have been reported against 'rawhide' during the Fedora Linux 38 development cycle.
Changing version to 38.

Comment 3 Steve Dickson 2023-07-20 17:10:04 UTC

specifying the -o mountproto=tcp6 causes ipv6 mount...