On Wed, 2020-06-10 at 12:01 -0500, David Wright wrote: > On Wed 10 Jun 2020 at 12:05:57 (-0400), Jim Popovitch wrote: > > Something that has always bugged me (and #debian hasn't yet answered) > > > > What establishes the IPv6 loopback ::1 address, and why is there no need > > for "iface lo inet6 loopback" in /etc/network/interfaces? > > AFAICT there's code in linux-source-4.19/net/ipv6/addrconf.c to make > sure that the loopback gets set up early enough. The comments are: > > /* The addrconf netdev notifier requires that loopback_dev > * has it's ipv6 private information allocated and setup > * before it can bring up and give link-local addresses > * to other devices which are up. > * > * Unfortunately, loopback_dev is not necessarily the first > * entry in the global dev_base list of net devices. In fact, > * it is likely to be the very last entry on that list. > * So this causes the notifier registry below to try and > * give link-local addresses to all devices besides loopback_dev > * first, then loopback_dev, which cases all the non-loopback_dev > * devices to fail to get a link-local address. > * > * So, as a temporary fix, allocate the ipv6 structure for > * loopback_dev first by hand. > * Longer term, all of the dependencies ipv6 has upon the loopback > * device and it being up should be removed. > > Cheers, > David. >
Ahh, thanks for that. -Jim P.
