fatal: ssh_dispatch_run_fatal: Connection reset by peer [preauth]

[Christian Hesse]

Hello everybody,

I have systemd set up to listen on ssh socket (:::22), the connection is
handled to sshd via socket activation. Usually this works perfectly fine.

However the service is checked from nagios. Sometimes the host logs:

systemd[1]: Started OpenSSH Per-Connection Daemon ([::1]:60865).
systemd[1]: Starting OpenSSH Per-Connection Daemon ([::1]:60865)...
systemd[1]: Started OpenSSH Per-Connection Daemon (127.0.0.1:41286).
systemd[1]: Starting OpenSSH Per-Connection Daemon (127.0.0.1:41286)...
sshd[2854]: Connection closed by ::1 [preauth]
sshd[2855]: fatal: ssh_dispatch_run_fatal: Connection reset by peer [preauth]

Looks like this happens if we have two incoming connection (::1 and
127.0.0.1 are checked) at the some time.
Why does this happen? Who's fault is it? As these are TCP connections I would
expect it is not a problem to know what packet belongs to what connection.
-- 
main(a){char*c=/*    Schoene Gruesse                         */"B?IJj;MEH"
"CX:;",b;for(a/*    Chris           get my mail address:    */=0;b=c[a++];)
putchar(b-1/(/*               gcc -o sig sig.c && ./sig    */b/42*2-3)*42);}
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