sshd "getpeername failed: Transport endpoint is not connected" error

[Darren Tucker]

On Wed, Dec 9, 2015 at 7:43 PM, Andrey Klimentev <andrei650816 at gmail.com> wrote:
> Hello, everybody.
>
> I've recently encountered a problem with OpenSSH server. Could you
> help me to troubleshoot it?
>
> I've configured 2 IP interfaces[1]: one with a public IP adress and
> one with a private address. When I connect[2] through the public
> interface (ens34), SSH works fine, but when I connect[3] through the
> private interface (ens32), I receive a rather cryptic message on my
> client - "ssh_exchange_identification: read: Connection reset by
> peer".

"reset by peer" usually means the TCP connection has been torn down
via a TCP RST packet.  This can be the other end crashing (although
from your logs that doesn't look to be the case here) or something
like a firewall sending a RST.

Do you have any firewall or packet filter in that network path?
iptables anti-spoofing rules?

> And this on my server - getpeername failed: Transport endpoint
> is not connected".

>From the failed traces:

debug1: rexec start in 4 out 4 newsock 4 pipe -1 sock 7
debug1: inetd sockets after dupping: 3, 3
debug1: getpeername failed: Transport endpoint is not connected
debug1: get_remote_port failed

Since this happens immediately after the server reexecs itself,
another possiblity is that somehow the descriptors are being marked
close-on-exec.  You can test this theory by adding "-r" to sshd's
command line to disable reexec.

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.