On 04/07/17 08:17, Rick Stevens wrote: > On 04/06/2017 02:45 PM, Stephen Morris wrote: >> On 4/6/17 9:20 AM, Ed Greshko wrote: >>> On 04/06/17 06:57, Stephen Morris wrote: >>>> Hi Ed, just as a side issue to this, because my ISP (I don't know >>>> about my VPN provider) IPv6 at all for anything, I was setting IPv6 to >>>> 'ignore' via Networkmanager in KDE (Gnome doesn't seem to have the >>>> same options) but that was causing messages in the logs at boot time >>>> about IPv6 not being ready. How do we stop the network from attempting >>>> to activate IPv6 and then producing these messages when it has been >>>> turned off? >>> (We inadvertently went off list...So I will reproduce what I sent Steve >>> here) >>> >>> Early AM here in Taiwan. No coffee yet. >>> >>> I think you are saying your ISP isn't providing IPv6 support at all and >>> that you'd like to totally disable IPv6. If that is the case then you >>> can do this by adding ipv6.disable=1 to the kernel boot parameters in >>> grub. >>> >>> If I misunderstood your question let me know and I'll try again after >>> coffee. >>> >>> Later, with still no coffee..... >>> >>> I decided to do a test and add ipv6.disable=1 to the kernel parameter on >>> one of my VM's. In the past, this was sufficient. However, doing only >>> this now results in selinux errors. To avoid those you also need to add >>> "net.ipv6.conf.all.disable_ipv6 = 1" to /etc/sysctl.conf. >> Your assessment was correct Ed. I meant to say that my ISP doesn't >> support IPv6 at all. >> >> Instead of setting the IPv6 options to 'Ignore' in the networkmanager >> definition for my router, I have set the option to 'Link-local', which >> has also stopped the boot time messages. What exactly does 'Link-local' >> actually do (my assumption was it has activated IPv6 addressing for >> local network routing but not activated IPv6 for internet routing)? > Uhm, sorta. A link-local address means those IPs will only be used > in the local LAN segment and should not attempt to traverse gateways. > > Link-local addresses are actual IP addresses. In IPV4, the allowed > addresses are inside the 169.254.1.0 - 169.254.254.255 range (note that > this is almost, but not quite the CIDR 169.254.0.0/16) but are NOT > mandatory. In IPV4, if you have a valid IPV4 address, that's good > enough for everything. > > NOTE: The link-local IPV4s look like they're routable since they're not > in the private IP networks 10.0.0.0/8, 172.16.0.0/12 or 192.168.0.0/16. > Since routers will not pass those link-local IPs along, they're really > not routable. > > For IPV6, link-local addresses are in fe80::/10 (to conform to /64 > requirements on LAN segments, it's often called fe80::/64) and ARE > mandatory (used for things like DHCPV6 and NDP). Unlike IPV4, IPV6 > _requires_ every interface to have (at least) a link-local address. If > the IPV6 interface is externally routable, it will require a second > IPV6 IP which is used for the external routes, so most IPV6 interfaces > you see will have two (or more) addresses associated with them. > > Confusing, ain't it? My brain starts to bleed every time I get into this > stuff. Grumph! Another thing worth mentioning. You can use the link-local addresses within the same LAN segment but you must specify the interface to be used. [egreshko@meimei ~]$ ping6 fe80::6025:85ec:2615:8969 connect: Invalid argument [egreshko@meimei ~]$ ping fe80::6025:85ec:2615:8969%enp2s0 PING fe80::6025:85ec:2615:8969%enp2s0(fe80::6025:85ec:2615:8969%enp2s0) 56 data bytes 64 bytes from fe80::6025:85ec:2615:8969%enp2s0: icmp_seq=1 ttl=64 time=0.383 ms 64 bytes from fe80::6025:85ec:2615:8969%enp2s0: icmp_seq=2 ttl=64 time=0.370 ms 64 bytes from fe80::6025:85ec:2615:8969%enp2s0: icmp_seq=3 ttl=64 time=0.300 ms 64 bytes from fe80::6025:85ec:2615:8969%enp2s0: icmp_seq=4 ttl=64 time=0.382 ms -- Fedora Users List - The place to go to get others to do the work for you _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx
