Why does NetworkManager report IPv6 related warnings when IPv6 is disabled in the kernel?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux (RHEL) 7 and above
  • NetworkManager
  • IPv6

Issue

  • Why does NetworkManager report IPv6 related warnings when IPv6 is disabled in the kernel?
NetworkManager[5621]: <warn>  [1657217781.6789] platform-linux: do-add-ip6-address[2001:db8::]: failure 95 (Operation not supported)
NetworkManager[5621]: <warn>  [1657217781.6789] platform-linux: do-add-ip6-address[2001:db8::]: failure 95 (Operation not supported)
NetworkManager[5621]: <warn>  [1657217781.6789] platform-linux: do-add-ip6-address[2001:db8::]: failure 95 (Operation not supported)

Resolution

Disable IPv6 on the NetworkManager connection and bounce the interface. The below commands disable IPv6 for the connection and will bounce the interface.

#nmcli con mod <conection name> ipv6.method disabled
#nmcli con down <conection name> 
#nmcli con up <conection name>

Root Cause

NetworkManager is trying to configure the IPv6 address. Because the existing NetworkManager connection has IPv6 enabled. But getting the above warnings since the IPv6 support is completely disabled at the kernel level.

Diagnostic Steps

  • Check if IPv6 is disabled at kernel.
  • Check if the NetworkManager connection has IPv6 enabled.

The below example shows IPv6 enabled as link-local in NetworkManager:

[root@node2.example.com~]# egrep  -o 'ipv6.disa[^ ]*' /proc/cmdline
ipv6.disable=1

[root@node2.example.com ~]# nmcli connection show enp1s0  | grep  ipv6.method
ipv6.method:                             link-local

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1 Comments

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TC Newbie 11 points
28 March 2023 6:22 PM

[root@ ~]# egrep -o 'ipv6.disa[^ ]*' /proc/cmdline ipv6.disable=1 [root@ ~]#

[root@ ~]# nmcli con sh team0|grep ipv6.method ipv6.method: disabled [root@ ~]#

Mar 28 15:16:11 NetworkManager[1929]: [1680027371.8307] platform-linux: do-add-ip6-address[2: fe80::56ce:9a42:4c6:2b8d]: failure 95 (Operation not supported) Mar 28 15:16:13 NetworkManager[1929]: [1680027373.8314] platform-linux: do-add-ip6-address[2: fe80::4d6c:36f0:8c00:bc65]: failure 95 (Operation not supported) Mar 28 15:16:15 NetworkManager[1929]: [1680027375.8335] ipv6ll[c6475db57668c8cc,ifindex=2]: changed: no IPv6 link local address to retry after Duplicate Address Detection failures (back off) Mar 28 15:16:25 NetworkManager[1929]: [1680027385.8346] platform-linux: do-add-ip6-address[2: fe80::f467:ef00:a67e:737d]: failure 95 (Operation not supported) Mar 28 15:16:27 NetworkManager[1929]: [1680027387.8359] platform-linux: do-add-ip6-address[2: fe80::8056:a5b3:cd93:4cdc]: failure 95 (Operation not supported) Mar 28 15:16:29 NetworkManager[1929]: [1680027389.8361] platform-linux: do-add-ip6-address[2: fe80::2778:18fe:af4c:1754]: failure 95 (Operation not supported) Mar 28 15:16:31 NetworkManager[1929]: [1680027391.8373] platform-linux: do-add-ip6-address[2: fe80::4990:3718:3886:7c4]: failure 95 (Operation not supported) Mar 28 15:16:33 NetworkManager[1929]: [1680027393.8395] platform-linux: do-add-ip6-address[2: fe80::56ce:9a42:4c6:2b8d]: failure 95 (Operation not supported) Mar 28 15:16:35 NetworkManager[1929]: [1680027395.8397] platform-linux: do-add-ip6-address[2: fe80::4d6c:36f0:8c00:bc65]: failure 95 (Operation not supported) Mar 28 15:16:37 NetworkManager[1929]: [1680027397.8418] ipv6ll[c6475db57668c8cc,ifindex=2]: changed: no IPv6 link local address to retry after Duplicate Address Detection failures (back off) Mar 28 15:16:47 NetworkManager[1929]: [1680027407.8430] platform-linux: do-add-ip6-address[2: fe80::f467:ef00:a67e:737d]: failure 95 (Operation not supported) Mar 28 15:16:49 NetworkManager[1929]: [1680027409.8449] platform-linux: do-add-ip6-address[2: fe80::8056:a5b3:cd93:4cdc]: failure 95 (Operation not supported) Mar 28 15:16:51 NetworkManager[1929]: [1680027411.8471] platform-linux: do-add-ip6-address[2: fe80::2778:18fe:af4c:1754]: failure 95 (Operation not supported) ^C [root@ ~]#

The server has en0, en1 as team0, ib0 and ib1 as infiniband and I made the commands above for all of them:

nmcli con mod ipv6.method disabled nmcli con down nmcli con up

Still logging....what else can be done?