[SOLVED] SSH from one TK1 to Another TK1 doesn't work

I have two devices, 192.168.11.104 and .238 (same subnet). Both devices can ping each other, neither device can ssh into the other. Both devices can ssh into other hosts. Other hosts can ssh into them both. They can both ssh into themselves.

$ ssh -vvv 192.168.11.238
OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /home/ubuntu/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.11.238 [192.168.11.238] port 22.
debug1: Connection established.
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/ubuntu/.ssh/id_rsa" as a RSA1 public key
debug1: identity file /home/ubuntu/.ssh/id_rsa type 1
debug1: identity file /home/ubuntu/.ssh/id_rsa-cert type -1
debug1: identity file /home/ubuntu/.ssh/id_dsa type -1
debug1: identity file /home/ubuntu/.ssh/id_dsa-cert type -1
debug1: identity file /home/ubuntu/.ssh/id_ecdsa type -1
debug1: identity file /home/ubuntu/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/ubuntu/.ssh/id_ed25519 type -1
debug1: identity file /home/ubuntu/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 pat OpenSSH_6.6.1* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "192.168.11.238" from file "/home/ubuntu/.ssh/known_hosts"
debug3: load_hostkeys: loaded 0 keys
debug1: SSH2_MSG_KEXINIT sent

and

$ ssh -vvv 192.168.11.104
OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /home/ubuntu/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.11.104 [192.168.11.104] port 22.
debug1: Connection established.
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/ubuntu/.ssh/id_rsa" as a RSA1 public key
debug1: identity file /home/ubuntu/.ssh/id_rsa type 1
debug1: identity file /home/ubuntu/.ssh/id_rsa-cert type -1
debug1: identity file /home/ubuntu/.ssh/id_dsa type -1
debug1: identity file /home/ubuntu/.ssh/id_dsa-cert type -1
debug1: identity file /home/ubuntu/.ssh/id_ecdsa type -1
debug1: identity file /home/ubuntu/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/ubuntu/.ssh/id_ed25519 type -1
debug1: identity file /home/ubuntu/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 pat OpenSSH_6.6.1* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "192.168.11.104" from file "/home/ubuntu/.ssh/known_hosts"
debug3: load_hostkeys: loaded 0 keys
debug1: SSH2_MSG_KEXINIT sent

What in the world is going on?

Adding their public keys to each other’s authorized_keys does not change the behavior either.

Can you run tail -f on both /var/log/auth.log and faillog (of the machine being connected to) and see what shows up as the other Jetson connects? Perhaps compare to what shows up when a working non-Jetson machine succeeds at logging in.

Also, if you leave out the verbose flags to ssh, are there any messages or does it just hang? If it just hangs, have you waited some long period of perhaps 5 minutes or more to see if it finally does something after a timeout?

The logs had nothing. I found the issue oddly by changing the MTU (i had changed it to 9000 for jumbo frames), though after reading about the downgrade of the nic to 10/100, I bet that’s why other things aren’t working.

$ sudo ifconfig eth0 mtu 1500

Caused the key exchange to work again. Seems like sshd has a bug.

I didn’t see this issue when ssh between TK1 device with default setting.
BTW, the MTU is 1500 by default.

Hi emrainey,

I have verified on my jetson boards, It is working fine. I can ssh in to one another with no hassle.

I could see from your logs that user sepcific ssh configuration is being read from “/home/ubuntu/.ssh/config” file, Have you purposefully created this or Do you have any other Remote Apps/Tools installed on your machine which did so.

Suggestion : Try with Root user or any other New user to rule out this situation.

–Bharat Pechetti

Please let me know your observations.

–Bharat Pechetti