Issue reliably ssh-ing into tx2

Autonomous Machines Jetson & Embedded Systems Jetson TX2
#1

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]

SSH on Jetson TX2 failing at random intervals
#2

Hi ericye16,

Please check your eth0 IP address and using below command to login via ssh:

ssh nvidia@[Eth0 IP address]
#3

Thanks for your suggestion, however that is not the issue:

eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh 169.254.6.188
The authenticity of host '169.254.6.188 (169.254.6.188)' can't be established.
ECDSA key fingerprint is SHA256:oTgKigtyuJgE0GInUM9EkZObS6bfjvfr2ENHU7j+1wE.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '169.254.6.188' (ECDSA) to the list of known hosts.
ssh_dispatch_run_fatal: Connection to 169.254.6.188 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
ssh_dispatch_run_fatal: Connection to 169.254.6.188 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
ssh_dispatch_run_fatal: Connection to 169.254.6.188 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
ssh_dispatch_run_fatal: Connection to 169.254.6.188 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
Connection to 169.254.6.188 closed by remote host.
Connection to 169.254.6.188 closed.
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
ssh_dispatch_run_fatal: Connection to 169.254.6.188 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
ssh_dispatch_run_fatal: Connection to 169.254.6.188 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
nvidia@169.254.6.188's password: 
Connection to 169.254.6.188 closed by remote host.
Connection to 169.254.6.188 closed.
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
ssh_dispatch_run_fatal: Connection to 169.254.6.188 port 22: incorrect signature
eric-robot@ericrobot-H370AORUSGAMING3WIFI:~$ ssh nvidia@169.254.6.188
nvidia@169.254.6.188's password: 
Welcome to Ubuntu 16.04 LTS (GNU/Linux 4.4.38-tegra aarch64)
#4

It sounds like the keys/fingerprints changed and you are being warned. Beware that if you have flashed you might change something on the Jetson which was previously memorized by the host.

On the host, if you look at “~/.ssh/known_hosts”, there will be one long line for each name@host you have previously answered that you want to trust the connection. Because you are using destination “nvidia@169.254.6.188” you will find at least one line with “169.254.6.188”. It looks like the “proper” way to remove the entry would be something like:

ssh-keygen -R 169.254.6.188

…though I usually just remove the line with an editor (in most cases there is no difference).

After that a new connect would ask again if you want to trust the connection. If you remove that line from your host (and if not using sudo, then for that user…if using sudo, then for root) does it start working again after asking if you trust the connection?

I usually back up a copy of each of my embedded system’s “/etc/ssh/” directory so as to not lose any host signature after a flash.

#5

Hi linuxdev,
I don’t think this is the issue because I made sure to clean the keys before connecting and also because it eventually let me through to password authentication, which it wouldn’t have done if the keys were mismatched. Also note that at the beginning of the pasted commands, ssh notes that it hasn’t seen a key for the IP address before and is just adding it, so stale keys are not the issue.

After further investigation, I think there is an issue with the ethernet controller/PHY on my TX2 board. When using my TX2 connected to my router over ethernet, I cannot connect to the internet reliably (visiting any site gives me security errors on chromium), but I have no trouble connecting to the internet over WiFi. The ethernet cable/router work for sure because my desktop computer uses them fine with no problem. I can also ssh reliably into the Jetson over WiFi, so it is definitely not an ssh library version error or anything like that.

I ended up flashing R28.1 and then completing the Jetpack install over Wifi, which isn’t ideal but worked. I’d still like to use ethernet later.
I can use WiFi for now but I am thinking of doing an RMA on my unit since I don’t know what else it could be and don’t see anyone else with this issue.

#6

If you do start working on wired ethernet again, then after some login issues have occurred, try posting the output of “ifconfig” for both PC and TX2. It’ll allow looking for issues such as drops, collisions, so on. If the PHY itself is not correct, then something would show up in that from one of the two systems. After this occurs you might also want to add the output of “route” on the system where the ssh command originates. Ssh itself can also be run with verbose with “-vvv” for detailed information on what it sees.

If you do RMA, then there is RMA information near the top of this:
https://devtalk.nvidia.com/default/topic/793798/embedded-systems/some-jetson-web-links/