SSH failed (read ECONNRESET) with release 140-145; Worked in release 139. SSH protocol error? Thanks.

I’m unable to connect using SSH access to RHEL (Redhat) from release 140-145. The same SSH connection worked in release 139.

SSH  Connecting to x.y.com.
 X  read ECONNRESET
 SSH   X  Remote rejected opening a shell channel: Error: Not connected

On the server side, it’s running OpenSSH_7.4p1. SSHD appears to be closing the connection because tabby didn’t pass identification string (see below).

Jul 8 12:43:28 x sshd[93603]: Did not receive identification string from 10.1.1.100 port 64842

Oddly, SSH in Release 140-145 works if I connect to Ubuntu/Debian, running OpenSSH 8.x (but failed if RHEL & OpenSSH 7.x). Unfortunately, I don’t own the RHEL, so can’t update SSHD on it.

Interestingly, Wireshark network capture on the client side, decodes those fragmented packet as “SSH” but malformed.

SSH Protocol
[Malformed Packet: SSH]
    [Expert Info (Error/Malformed): Malformed Packet (Exception occurred)]

When I failback to putty, the 1st packet gets decoded as SSHv2 (see below).

SSH Protocol
    Protocol: SSH-2.0-PuTTY_Release_0.71
    [Direction: client-to-server]

Thanks for your great work on Tabby! Love it as do many others! 👍🏼

[Eugeny]

Build should be done soon: https://github.com/Eugeny/tabby/actions/runs/1018258488

<div> GitHub</div><div>Eugeny/tabby</div><div>A terminal for a more modern age (formerly Terminus) - Eugeny/tabby</div>

[Eugeny]

Hi, thanks for the detailed report. It appears that Wireshark fails to parse the packet because node-ssh2 sends the ident string and CRLF in two separate TCP packets. I’ve patched them together and now Wireshark sees the SSH packet structure again:

That said, it already worked before with a CentOS machine running openssh-7.4p1-21.el7.x86_64.

I’ll push this change anyway - let’s see if it helps