[CPANEL-21359] IPv6 stops working after reboot on CentOS 6 systems

janipewter

• April 15, 2018 17:42

I have IPv6 correctly set up and working on my server. You can verify this by having a look at one of my sites: - Removed - Obviously you need to have IPv6 in order to reach the site over IPv6. This domain should resolve to - Removed - Now the problem is that when I restart the server, none of my sites are reachable over IPv6. If I try to ping their IPv6 addresses, it just times out. This is a huge problem because I have some critical email accounts on my server which I import to Gmail, and by default Gmail will connect over IPv6 if it is available at the remote server, WHICH IT IS, but not working. This week I missed some important emails after I rebooted the server 3 days ago for a kernel upgrade and forgot about the IPv6 not working. Now in order to fix it, in WHM I go to Assign IPv6 Address, and then just disable and re-enable all of the sites. Then everything works perfectly as before. I can replicate this bug 100% of the time. Simply enable IPv6 on any account and reboot the server. DNS will still resolve the IPv6 address, but it won't respond to ping or anything else. Which is really annoying because it breaks a lot of stuff.

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  cPanelMichael

  • April 16, 2018 16:35

  Hello @janipewter, Can you run the following commands on this system and let us know the output? grep ONBOOT /etc/sysconfig/network-scripts/* grep NM_CONTROLLED /etc/sysconfig/network-scripts/*
  The output shouldn't show any identifying server information, but ensure to replace the output with examples before posting it here if it does. Thank you.

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  janipewter

  • April 16, 2018 16:41

  Here you go: [quote][root@srv01 ~]# grep ONBOOT /etc/sysconfig/network-scripts/* /etc/sysconfig/network-scripts/ifcfg-eth0:ONBOOT="yes" /etc/sysconfig/network-scripts/ifcfg-eth1:ONBOOT="no" /etc/sysconfig/network-scripts/ifcfg-eth2:ONBOOT="no" /etc/sysconfig/network-scripts/ifcfg-eth3:ONBOOT="no" /etc/sysconfig/network-scripts/ifcfg-lo:ONBOOT=yes /etc/sysconfig/network-scripts/ifup:if [ "foo$2" = "fooboot" ] && [ "${ONBOOT}" = "no" -o "${ONBOOT}" = "NO" ] /etc/sysconfig/network-scripts/ifup-ippp:if [ "${2}" = "boot" -a "${ONBOOT}" = "no" ]; then /etc/sysconfig/network-scripts/ifup-isdn:if [ "${2}" = "boot" -a "${ONBOOT}" = "no" ]; then /etc/sysconfig/network-scripts/ifup-plip:if [ "foo$2" = "fooboot" -a "${ONBOOT}" = "no" ] /etc/sysconfig/network-scripts/ifup-plusb:if [ "foo$2" = "fooboot" -a "${ONBOOT}" = "no" ] /etc/sysconfig/network-scripts/ifup-ppp:if [ "${2}" = "boot" -a "${ONBOOT}" = "no" ]; then
  [quote] [root@srv01 ~]# grep NM_CONTROLLED /etc/sysconfig/network-scripts/* /etc/sysconfig/network-scripts/ifcfg-eth0:NM_CONTROLLED="yes" /etc/sysconfig/network-scripts/ifcfg-eth1:NM_CONTROLLED="yes" /etc/sysconfig/network-scripts/ifcfg-eth2:NM_CONTROLLED="yes" /etc/sysconfig/network-scripts/ifcfg-eth3:NM_CONTROLLED="yes" /etc/sysconfig/network-scripts/network-functions: ! is_false $NM_CONTROLLED && is_nm_running && USE_NM=true
  

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  cPanelMichael

  • April 16, 2018 16:56

  Hello, Could you open a support ticket so we can take a closer look at the IPv6 configuration and rule out any issues caused by the cPanel & WHM software?

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  janipewter

  • April 16, 2018 17:20

  Thanks, support ticket opened. Your Support Request ID is: 9443101

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  cPanelMichael

  • June 22, 2018 16:30

  Hello, To update, internal case CPANEL-21359 is now open to investigate an issue where IPv6 addresses are not bound to the server at boot time on CentOS 6 systems. I'll monitor the case and update this thread with more information as it becomes available. In the meantime, the workaround is to run the following command once the server resumes after a reboot: /scripts/restartsrv_cpipv6
  Thank you.

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  cPanelMichael

  • October 22, 2018 21:00

  Hello, To update, this is fixed in

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