I have been having reliably ssh-ing into the tx2, even when the host computer and jetson are directly connected to each other via an ethernet cable. This is what I see:
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
ssh_dispatch_run_fatal: Connection to 10.42.0.200 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
Connection to tegra-ubuntu.local closed by remote host.
Connection to tegra-ubuntu.local closed.
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
ssh_dispatch_run_fatal: Connection to 10.42.0.200 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
ssh_dispatch_run_fatal: Connection to 10.42.0.200 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
ssh_dispatch_run_fatal: Connection to 10.42.0.200 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
ssh_dispatch_run_fatal: Connection to 10.42.0.200 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
ssh_dispatch_run_fatal: Connection to 10.42.0.200 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~ ssh nvidia@tegra-ubuntu.local
ssh_dispatch_run_fatal: Connection to 10.42.0.200 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@tegra-ubuntu.local
Welcome to Ubuntu 16.04 LTS (GNU/Linux 4.4.38-tegra aarch64)
Possibly related: When I try to use Jetpack to flash the board, I see these errors:
E: Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/xenial/main/binary-arm64/Packages 404 Not Found [IP: 2001:67c:1560:8001::11 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/main/binary-arm64/Packages 404 Not Found [IP: 2001:67c:1560:8001::11 80]
E: Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/xenial-updates/main/binary-arm64/Packages 404 Not Found [IP: 2001:67c:1560:8001::11 80]
E: Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/xenial-backports/main/binary-arm64/Packages 404 Not Found [IP: 2001:67c:1560:8001::11 80]