* Gert Doering > +Note 2: if you do an IPv6+IPv4 dual-stack bind on a Linux machine with > +multiple IPv4 address, connections to IPv4 addresses will not work > +right on kernels before 3.14, due to missing kernel support for the > +IPv4-mapped case.
This isn't entirely accurate. There are two patches that are required for this to work: «ipv6: make IPV6_RECVPKTINFO work for ipv4 datagrams» https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4b261c75a99f29c93a0b6babfc180cdf566bd654 «ipv6: honor IPV6_PKTINFO with v4 mapped addresses on sendmsg» https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c8e6ad0829a723a74cd2fea9996a3392d2579a18 Only the first one is in Linux 3.14, the second one is not (it first appeared in 3.15-rc1). You should probably say «before 3.15» instead. Another thing worth noting though, is that Ubuntu backported both patches to the 3.13-based kernel they are shipping as part of Ubuntu 14.04 «Trusty». So it works out of the box there, which is great news because it's a "Long Term Support" release that will probably be popular on servers in the years to come. The patches will eventually make it into the previous LTS release 12.04 «Precise» too, as part of the upcoming 12.04.5 point release (expected in August). https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1284535 Tore
