Juliusz Chroboczek <j...@irif.fr> writes: > Hi, > > I'm in the process of merging v4-via-v6 into mainline babeld, and I need > some advice about the default configuration. > > V4-via-v6, is described here: > > https://datatracker.ietf.org/doc/html/draft-ietf-babel-v4viav6 > > It's a technique that allows an IPv6-only router to forward IPv4 packets, > which makes it easier to administer a double-stack network, since only > IPv6 addresses need to be allocated inside the network. However, > a v4-via-v6 router needs to be able to originate ICMPv4 packets, and these > packets need to have a source address. > > I haven't done extensive testing yet, but my preliminary investigations > indicate that the Linux kernel behaves as follows: > > - if the router has an IPv4 address on at least one interface, the > address is borrowed as the source of the ICMPv4 packet; > - if the router has no IPv4 address at all, no ICMPv4 packet is sent, > which may cause blackholes. > > The issue is describes in Section 3 of the draft, which suggests using the > IPv4 dummy address 192.0.0.8 when no IPv4 address is available. Using the > dummy address will require some minor surgery to the Linux kernel, and > I haven't implemented it yet. So while we wait for somebody (me or > someone else) to implement support for the dummy address, what should > babeld's default behaviour be? > > 1. Disable v4-via-v6 by default, and assume that an administrator who > enables it knows what they're doing? > 2. Check for IPv4 addresses, and enable v4-via-v6 automatically if there > is at least one IPv4 address? > 3. 3=1+2, behave like (2), but allow overriding the daemon's decision? > > Any better ideas?
Not really - 3 would be my preference of the above, I think. Do the right thing by default, but don't second-guess the user if they explicitly ask for a particular behaviour... :) -Toke _______________________________________________ Babel-users mailing list Babel-users@alioth-lists.debian.net https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/babel-users