Hmm, there may be MTU issues, but I think I have just routing problems to start. All of my traffic is going to go out Level3 (at least right now). Doing a trace from level3 (Cincinnati - which is where our circuits come from) results in timeouts: Traceroute results from Cincinnati, OH to 2400:cb00:2048:1::8d65:7fda 1 vl-5.bar1.Cincinatti1.Level3.net (2001:1900:23::1) 0 msec 0 msec 0 msec 2 vl-4066.car2.Chicago1.Level3.net (2001:1900:4:1::27D) 8 msec 8 msec 8 msec 3 vl-4080.car1.Chicago1.Level3.net (2001:1900:4:1::15) 40 msec 60 msec 8 msec 4 vl-4040.edge1.Chicago2.Level3.net (2001:1900:4:1::1E) 8 msec 8 msec 4 msec 5 vl-4042.edge6.Denver1.Level3.net (2001:1900:4:1::35) 32 msec 84 msec 28 msec 6 vl-4060.car2.Seattle1.Level3.net (2001:1900:4:1::10A) 92 msec 56 msec 56 msec 7 2001:1900:1B:2::9 60 msec 60 msec 60 msec 8 * * * 9 * * * 10 * * * 11 * * * 12 * * * 13 * * * 14 * * * 15 * * * 16 * * * 17 * * * 18 * * * 19 * * * 20 * * * timeout ! Guess I should open a ticket upstream and maybe have Level3 poke Cloudflare ?