[X2Go-Dev] X2go Mac client and Red Hat 7 server

Mon May 11 18:16:07 CEST 2015

See my replies below:

> When using "sudo sshd -ddd -p 18935" like suggested by Mihai, I'm
> getting "sshd re-exec requires execution with an absolute path" and
> the shell prompt returns.

I got this last Friday and figured the absolute path

> Which means there is no SSHD running on port 18935.  (Verifiable with
> "netstat -ant | grep ':18935' | wc -l" - that should return a number
> greater than 0 if SSHD is running on Port 18935.)

Returned the number 2

> sudo $(which sshd) -ddd -p 18935
> Leave that commandline window open, important debug information will
>appear there.

# $(which sshd) -ddd -p 18935
debug2: load_server_config: filename /etc/ssh/sshd_config
debug2: load_server_config: done config len = 848
debug2: parse_server_config: config /etc/ssh/sshd_config len 848
debug3: /etc/ssh/sshd_config:28 setting HostKey /etc/ssh/ssh_host_rsa_key
debug3: /etc/ssh/sshd_config:30 setting HostKey /etc/ssh/ssh_host_ecdsa_key
debug3: /etc/ssh/sshd_config:42 setting SyslogFacility AUTHPRIV
debug3: /etc/ssh/sshd_config:44 setting LogLevel VERBOSE
debug3: /etc/ssh/sshd_config:56 setting MaxAuthTries 5
debug3: /etc/ssh/sshd_config:64 setting AuthorizedKeysFile
.ssh/authorized_keys
debug3: /etc/ssh/sshd_config:73 setting RhostsRSAAuthentication yes
debug3: /etc/ssh/sshd_config:76 setting HostbasedAuthentication yes
debug3: /etc/ssh/sshd_config:82 setting IgnoreRhosts no
debug3: /etc/ssh/sshd_config:87 setting PasswordAuthentication yes
debug3: /etc/ssh/sshd_config:91 setting ChallengeResponseAuthentication yes
debug3: /etc/ssh/sshd_config:102 setting GSSAPIAuthentication yes
debug3: /etc/ssh/sshd_config:104 setting GSSAPICleanupCredentials yes
debug3: /etc/ssh/sshd_config:120 setting UsePAM yes
debug3: /etc/ssh/sshd_config:126 setting X11Forwarding yes
debug3: /etc/ssh/sshd_config:133 setting UsePrivilegeSeparation sandbox

debug3: /etc/ssh/sshd_config:149 setting Banner /etc/banners/sshd
debug3: /etc/ssh/sshd_config:152 setting AcceptEnv LANG LC_CTYPE
LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
debug3: /etc/ssh/sshd_config:153 setting AcceptEnv LC_PAPER LC_NAME
LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
debug3: /etc/ssh/sshd_config:154 setting AcceptEnv LC_IDENTIFICATION
LC_ALL LANGUAGE
debug3: /etc/ssh/sshd_config:155 setting AcceptEnv XMODIFIERS
debug3: /etc/ssh/sshd_config:158 setting Subsystem sftp
/usr/libexec/openssh/sftp-server
debug1: sshd version OpenSSH_6.4, OpenSSL 1.0.1e-fips 11 Feb 2013
debug3: Incorrect RSA1 identifier
debug1: read PEM private key done: type RSA
debug3: Incorrect RSA1 identifier
debug3: Could not load "/etc/ssh/ssh_host_rsa_key" as a RSA1 public key
debug1: private host key: #0 type 1 RSA
debug3: Incorrect RSA1 identifier
debug1: read PEM private key done: type ECDSA
debug3: Incorrect RSA1 identifier
debug3: Could not load "/etc/ssh/ssh_host_ecdsa_key" as a RSA1 public key
debug1: private host key: #1 type 3 ECDSA
debug1: rexec_argv[0]='/sbin/sshd'
debug1: rexec_argv[1]='-ddd'
debug1: rexec_argv[2]='-p'
debug1: rexec_argv[3]='18935'
debug3: oom_adjust_setup
Set /proc/self/oom_score_adj from 0 to -1000
debug2: fd 3 setting O_NONBLOCK
debug1: Bind to port 18935 on 0.0.0.0.
Server listening on 0.0.0.0 port 18935.
debug2: fd 4 setting O_NONBLOCK
debug3: sock_set_v6only: set socket 4 IPV6_V6ONLY
debug1: Bind to port 18935 on ::.
Server listening on :: port 18935.

> With that window open, try connecting with X2GoClient to
>128.149.23.102:18935.
% /Applications/x2goclient.app/Contents/MacOS/x2goclient ; exit;
x2go-INFO-1> "Starting x2goclient..."
x2go-WARNING-1> "Can't load translator: :/i18n/x2goclient_en_us"
x2go-WARNING-2> "Can't load translator: :/i18n/qt_en_US"
x2go-INFO-3> "Started  x2goclient."
Object::connect: No such slot SessionWidget::slot_emitSettings()
Object::connect: No such slot SessionWidget::slot_emitSettings()
Object::connect: No such signal SessionWidget::directRDP(bool)
Object::connect: No such signal
SessionWidget::settingsChanged(QString,QString,QString)
2015-05-11 09:15:19.797 x2goclient[21241:1652401] modalSession has been
exited prematurely - check for a reentrant call to endModalSession:
x2go-INFO-8> "Starting connection to server: 128.149.23.102:18935"
x2go-ERROR-2> "Connection Error(Cannot connect to 128.149.23.102:18935):
Connection refused"

On 5/11/15, 9:05 AM, "Real, Elizabeth (392K)"
<Elizabeth.Real at jpl.nasa.gov> wrote:

>Here are the outputs from RH7 server and Mac client:
>
>RH7 server:
># /usr/sbin/sshd -ddd -p 18935
>debug2: load_server_config: filename /etc/ssh/sshd_config
>debug2: load_server_config: done config len = 848
>debug2: parse_server_config: config /etc/ssh/sshd_config len 848
>debug3: /etc/ssh/sshd_config:28 setting HostKey /etc/ssh/ssh_host_rsa_key
>debug3: /etc/ssh/sshd_config:30 setting HostKey
>/etc/ssh/ssh_host_ecdsa_key
>debug3: /etc/ssh/sshd_config:42 setting SyslogFacility AUTHPRIV
>debug3: /etc/ssh/sshd_config:44 setting LogLevel VERBOSE
>debug3: /etc/ssh/sshd_config:56 setting MaxAuthTries 5
>debug3: /etc/ssh/sshd_config:64 setting AuthorizedKeysFile
>.ssh/authorized_keys
>debug3: /etc/ssh/sshd_config:73 setting RhostsRSAAuthentication yes
>debug3: /etc/ssh/sshd_config:76 setting HostbasedAuthentication yes
>debug3: /etc/ssh/sshd_config:82 setting IgnoreRhosts no
>debug3: /etc/ssh/sshd_config:87 setting PasswordAuthentication yes
>debug3: /etc/ssh/sshd_config:91 setting ChallengeResponseAuthentication
>yes
>debug3: /etc/ssh/sshd_config:102 setting GSSAPIAuthentication yes
>debug3: /etc/ssh/sshd_config:104 setting GSSAPICleanupCredentials yes
>debug3: /etc/ssh/sshd_config:120 setting UsePAM yes
>debug3: /etc/ssh/sshd_config:126 setting X11Forwarding yes
>debug3: /etc/ssh/sshd_config:133 setting UsePrivilegeSeparation sandbox		
>debug3: /etc/ssh/sshd_config:149 setting Banner /etc/banners/sshd
>debug3: /etc/ssh/sshd_config:152 setting AcceptEnv LANG LC_CTYPE
>LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
>debug3: /etc/ssh/sshd_config:153 setting AcceptEnv LC_PAPER LC_NAME
>LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
>debug3: /etc/ssh/sshd_config:154 setting AcceptEnv LC_IDENTIFICATION
>LC_ALL LANGUAGE
>debug3: /etc/ssh/sshd_config:155 setting AcceptEnv XMODIFIERS
>debug3: /etc/ssh/sshd_config:158 setting Subsystem
>sftp	/usr/libexec/openssh/sftp-server
>debug1: sshd version OpenSSH_6.4, OpenSSL 1.0.1e-fips 11 Feb 2013
>debug3: Incorrect RSA1 identifier
>debug1: read PEM private key done: type RSA
>debug3: Incorrect RSA1 identifier
>debug3: Could not load "/etc/ssh/ssh_host_rsa_key" as a RSA1 public key
>debug1: private host key: #0 type 1 RSA
>debug3: Incorrect RSA1 identifier
>debug1: read PEM private key done: type ECDSA
>debug3: Incorrect RSA1 identifier
>debug3: Could not load "/etc/ssh/ssh_host_ecdsa_key" as a RSA1 public key
>debug1: private host key: #1 type 3 ECDSA
>debug1: rexec_argv[0]='/usr/sbin/sshd'
>debug1: rexec_argv[1]='-ddd'
>debug1: rexec_argv[2]='-p'
>debug1: rexec_argv[3]='18935'
>debug3: oom_adjust_setup
>Set /proc/self/oom_score_adj from 0 to -1000
>debug2: fd 3 setting O_NONBLOCK
>debug1: Bind to port 18935 on 0.0.0.0.
>Server listening on 0.0.0.0 port 18935.
>debug2: fd 4 setting O_NONBLOCK
>debug3: sock_set_v6only: set socket 4 IPV6_V6ONLY
>debug1: Bind to port 18935 on ::.
>Server listening on :: port 18935.
>
>
>Mac client:
>% ssh -p 18935 root at joey
>ssh: connect to host joey port 18935: Connection refused
>
>________________________________________
>From: Real, Elizabeth (392K)
>Sent: Thursday, May 07, 2015 3:23 PM
>To: Mihai Moldovan; x2go-dev at lists.x2go.org
>Subject: Re: [X2Go-Dev] X2go Mac client and Red Hat 7 server
>
>RH7 server: setup  debug and set sshd port 18935
>
>Client: configured x2goclient to connect to port 18935 but got connection
>refused
>x2go-INFO-8> "Starting connection to server: 128.149.23.102:18935"
>x2go-ERROR-2> "Connection Error(Cannot connect to 128.149.23.102:18935):
>Connection refused"
>
>
>
>On 5/7/15, 12:41 PM, "Mihai Moldovan" <ionic at ionic.de> wrote:
>
>>On 06.05.2015 11:55 PM, Real, Elizabeth (392K) wrote:
>>> Any other ideas?
>>
>>No new information and you have done nothing wrong.
>>
>>Looks like you will need to get your hands dirty.
>>
>>Please start sshd manually as root on the RH 7 machine:
>>
>>sudo sshd -ddd -p 18935
>>
>>It should be running in the foreground, outputting debug information and
>>listening on port 18935 (feel free to change this to whatever you feel
>>suitable,
>>it doesn't matter as long it as the port is unused and not colling with
>>anything
>>else you might use.
>>
>>Then, configure x2goclient to connect to that port and start a session.
>>
>>You should see additional debug information printed by sshd... hopefully
>>hinting
>>at what might have gone awry.
>>
>>
>>
>>Mihai
>>
>