Hi,
BackupPC has been working on my system for quite a while, but now it consequently fails after about 7 seconds. For this case, BackupPC server and client refer to the same machine. Contents of last bad XferLOG:

    Running: /usr/bin/ssh -q -x -n -l root virgo.ssc.kalliance.nl env LC_ALL=C /usr/bin/gtar -c -v -f - -C / --totals ./home ./etc ./data/Afbeeldingen ./data/Documenten ./data/Muziek
    full backup started for directory /
    Xfer PIDs are now 22662,22661
    Tar exited with error 65280 () status
    tarExtract: Done: 0 errors, 0 filesExist, 0 sizeExist, 0 sizeExistComp, 0 filesTotal, 0 sizeTotal
    Got fatal error during xfer (No files dumped for share /)
    Backup aborted (No files dumped for share /)
    Not saving this as a partial backup since it has fewer files than the prior one (got 0 and 0 files versus 0)


You've probably seen this error before, usually pointing to a misconfiguration of ssh somewhere. I read the manuals, did quite some goole-ing but still I am stuck.
I'm pretty sure I set up ssh correctly, as this works lika a charm. I started a shell for backuppc and dit some checks:

    -bash-4.2$ id
    UID=992(backuppc) GID=989(backuppc) groepen=989(backuppc)
    -bash-4.2$ hostname
    virgo.ssc.kalliance.nl
    -bash-4.2$ ping virgo.ssc.kalliance.nl -c 1
    PING virgo.ssc.kalliance.nl (192.168.204.140) 56(84) bytes of data.
    64 bytes from virgo.ssc.kalliance.nl (192.168.204.140): icmp_seq=1 ttl=64 time=0.073 ms

    --- virgo.ssc.kalliance.nl ping statistics ---
    1 packets transmitted, 1 received, 0% packet loss, time 0ms
    rtt min/avg/max/mdev = 0.073/0.073/0.073/0.000 ms
    -bash-4.2$
ssh -l root virgo.ssc.kalliance.nl whoami
    root

    -bash-4.2$
ssh -l root -o PreferredAuthentications="publickey" virgo.ssc.kalliance.nl whoami
    root



For troubleshooting purposes, removed the -q option for the tar xfer-method in config.pl:

    $Conf{TarClientCmd} = '$sshPath -x -n -l root $host'



Requesting a full backup in the web interface gave me almost the same message:

    Running: /usr/bin/ssh -x -n -l root virgo.ssc.kalliance.nl env LC_ALL=C /usr/bin/gtar -c -v -f - -C / --totals ./home ./etc ./data/Afbeeldingen ./data/Documenten ./data/Muziek
    full backup started for directory /
    Xfer PIDs are now 22695,22694
    ssh_exchange_identification: Connection closed by remote host
    Tar exited with error 65280 () status
    tarExtract: Done: 0 errors, 0 filesExist, 0 sizeExist, 0 sizeExistComp, 0 filesTotal, 0 sizeTotal
    Got fatal error during xfer (No files dumped for share /)
    Backup aborted (No files dumped for share /)
    Not saving this as a partial backup since it has fewer files than the prior one (got 0 and 0 files versus 0)

Please note the ssh_exchange_identification: Connection closed by remote host

That's funny....
I started pointing my attention to sshd: I started another shell for root, stopped the sshd background service, and started sshd in foreground:

    [root@virgo ~]# service sshd stop
    Redirecting to /bin/systemctl stop  sshd.service
    [root@virgo ~]# /usr/sbin/sshd -d
    debug1: sshd version OpenSSH_6.2, OpenSSL 1.0.1e-fips 11 Feb 2013
    debug1: read PEM private key done: type RSA
    debug1: private host key: #0 type 1 RSA
    debug1: read PEM private key done: type DSA
    debug1: private host key: #1 type 2 DSA
    debug1: read PEM private key done: type ECDSA
    debug1: private host key: #2 type 3 ECDSA
    debug1: rexec_argv[0]='/usr/sbin/sshd'
    debug1: rexec_argv[1]='-d'
    Set /proc/self/oom_score_adj from 0 to -1000
    debug1: Bind to port 22 on 0.0.0.0.
    Server listening on 0.0.0.0 port 22.
    debug1: Bind to port 22 on ::.
    Server listening on :: port 22.

Again, I requested a full backup from the web-interface: no updates in the root shell with sshd running in foreground. Huh?
To be sure, I re-did a ssh -l root -o PreferredAuthentications="publickey" virgo.ssc.kalliance.nl whoami from the backuppc shell, which still works like a charm (again), and updates in the root shell with sshd running in foreground.

Looks like an address resolution issue, but I really don't know where to go from here. Please be informed that I also run IPA on this machine....

I appreciate any reply...
Regards
Martin