Tag: ipv6

  • How to configure IPv6 on OVH AlmaLinux 8 server

    How to configure IPv6 on OVH AlmaLinux 8 server

    First, find the network interface used by the server with ip a command.

    [root@15-204-47-122 ~]# ip a
    1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
           valid_lft forever preferred_lft forever
        inet6 ::1/128 scope host 
           valid_lft forever preferred_lft forever
    2: eno1:  mtu 1500 qdisc mq state UP group default qlen 1000
        link/ether a8:a1:59:c0:de:80 brd ff:ff:ff:ff:ff:ff
        altname enp3s0f0
        inet 15.204.47.122/24 brd 15.204.47.255 scope global eno1
           valid_lft forever preferred_lft forever
        inet6 fe80::aaa1:59ff:fec0:de80/64 scope link 
           valid_lft forever preferred_lft forever
    3: enp3s0f1:  mtu 1500 qdisc noop state DOWN group default qlen 1000
        link/ether a8:a1:59:c0:de:81 brd ff:ff:ff:ff:ff:ff
    4: enp0s20f0u8u3c2:  mtu 1500 qdisc noop state DOWN group default qlen 1000
        link/ether 5a:58:d0:03:8e:b3 brd ff:ff:ff:ff:ff:ff
    [root@15-204-47-122 ~]# 
    

    The interface eno1 has the public IPv4 address of the server associated, so it is the public interface used by the server.

    Find the IPv6 IP address and gateway, This you can find in the OVH Manager server details page.

    OVH Server manager network details IPv6

    Edit ifcfg file for the network interface

    vi /etc/sysconfig/network-scripts/ifcfg-eno1 
    

    At the end of the configuration, add

    IPV6INIT=yes
    IPV6_AUTOCONF=no
    IPV6_FAILURE_FATAL=no
    IPV6ADDR=2604:2dc0:200:1f7a::/64
    

    2604:2dc0:200:1f7a::/64 – is the IPv6 IP address found in OVH Manager.

    Here is the full configuration

    BOOTPROTO=static
    DEVICE=eno1
    HWADDR=a8:a1:59:c0:de:80
    IPADDR=15.204.47.122
    NETMASK=255.255.255.0
    GATEWAY=15.204.47.254
    ONBOOT=yes
    TYPE=Ethernet
    USERCTL=no
    IPV6INIT=yes
    IPV6_AUTOCONF=no
    IPV6_FAILURE_FATAL=no
    IPV6ADDR=2604:2dc0:200:1f7a::/64
    

    Create route file

    vi /etc/sysconfig/network-scripts/route6-eno1 
    

    Add

    2604:2dc0:0200:1fff:00ff:00ff:00ff:00ff dev eno1
    default via 2604:2dc0:0200:1fff:00ff:00ff:00ff:00ff
    

    Here ‘2604:2dc0:0200:1fff:00ff:00ff:00ff:00ff” is gateway address you get from OVH Manager server network page. eno1 is your public network interface name.

    After reboot, the IPv6 network will work on the server.

    Back to IP

  • Disable IPv6

    To disable IPv6, edit

    vi /etc/sysctl.conf
    

    Add following

    net.ipv6.conf.all.disable_ipv6 = 1
    net.ipv6.conf.default.disable_ipv6 = 1
    net.ipv6.conf.lo.disable_ipv6 = 1
    

    run

    sysctl -p

    IPv6 config for RHEL

    BOOTPROTO=dhcp
    DEFROUTE=yes
    DEVICE=eth0
    DHCLIENT_SET_DEFAULT_ROUTE=yes
    HWADDR=fa:16:3e:83:96:4e
    IPV6ADDR=2607:5300:405:300::16dc/56
    IPV6INIT=yes
    IPV6_AUTOCONF=no
    IPV6_DEFAULTGW=2607:5300:405:300::1
    IPV6_FORCE_ACCEPT_RA=no
    MTU=1500
    ONBOOT=yes
    TYPE=Ethernet
    USERCTL=no

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