When I run ssh -X my_host I get the error: "X11 forwarding request failed on channel 0". (ssh -Y my_host gives the same error)
My host is a Gentoo Linux machine and my client is a macOS Catalina. Both host and client have xauth installed. The client has XQuartz-2.7.11 installed.
I have added the lines ForwardX11 yes and X11UseLocalhost no to the /etc/ssh/ssh_config file on the host, but that did not help.
Is there any way to solve this problem?
Possibly relevant information:
xauth list $DISPLAYgives no output on host nor on client.- I have added
XAuthLocation /opt/X11/bin/xauth,ForwardX11Trusted yesandForwardX11 yesin the ".ssh/config" file of the client.
Edit: the last lines of ssh -vvvX my_host are:
Authenticated to ******. debug1: channel 0: new [client-session] debug3: ssh_session2_open: channel_new: 0 debug2: channel 0: send open debug3: send packet: type 90 debug1: Requesting debug3: send packet: type 80 debug1: Entering interactive session. debug1: pledge: exec debug3: receive packet: type 80 debug1: client_input_global_request: rtype want_reply 0 debug3: receive packet: type 4 debug1: Remote: /home/user/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding debug3: receive packet: type 4 debug1: Remote: /home/user/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding debug3: receive packet: type 91 debug2: channel_input_open_confirmation: channel 0: callback start debug2: x11_get_proto: /opt/X11/bin/xauth list /private/tmp/com.apple.launchd.MRsK0ea50W/org.macosforge.xquartz:0 2>/dev/null debug1: Requesting X11 forwarding with authentication spoofing. debug2: channel 0: request x11-req confirm 1 debug3: send packet: type 98 debug2: fd 3 setting TCP_NODELAY debug3: ssh_packet_set_tos: set IP_TOS 0x48 debug2: client_session2_setup: id 0 debug2: channel 0: request pty-req confirm 1 debug3: send packet: type 98 debug1: Sending environment. debug3: Ignored env CONDA_DEFAULT_ENV debug3: Ignored env CONDA_EXE debug3: Ignored env CONDA_PREFIX debug3: Ignored env CONDA_PROMPT_MODIFIER debug3: Ignored env CONDA_PYTHON_EXE debug3: Ignored env CONDA_SHLVL debug3: Ignored env DISPLAY debug3: Ignored env HOME debug3: Ignored env JAVA_HOME debug1: Sending env LC_CTYPE = UTF-8 debug2: channel 0: request env confirm 0 debug3: send packet: type 98 debug3: Ignored env LOGNAME debug3: Ignored env LaunchInstanceID debug3: Ignored env PATH debug3: Ignored env PWD debug3: Ignored env SECURITYSESSIONID debug3: Ignored env SHELL debug3: Ignored env SHLVL debug3: Ignored env SSH_AUTH_SOCK debug3: Ignored env TERM debug3: Ignored env TERM_PROGRAM debug3: Ignored env TERM_PROGRAM_VERSION debug3: Ignored env TERM_SESSION_ID debug3: Ignored env TMPDIR debug3: Ignored env USER debug3: Ignored env XPC_FLAGS debug3: Ignored env XPC_SERVICE_NAME debug3: Ignored env _CE_CONDA debug3: Ignored env _CE_M debug3: Ignored env __CF_USER_TEXT_ENCODING debug2: channel 0: request shell confirm 1 debug3: send packet: type 98 debug2: channel_input_open_confirmation: channel 0: callback done debug2: channel 0: open confirm rwindow 0 rmax 32768 debug3: receive packet: type 100 debug2: channel_input_status_confirm: type 100 id 0 X11 forwarding request failed on channel 0 debug3: receive packet: type 99 debug2: channel_input_status_confirm: type 99 id 0 debug2: PTY allocation request accepted on channel 0 debug2: channel 0: rcvd adjust 2097152 debug3: receive packet: type 99 debug2: channel_input_status_confirm: type 99 id 0 debug2: shell request accepted on channel 0 log of host:
Aug 31 15:44:52 Jimmy sshd[12245]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=**** user=root Aug 31 15:44:52 Jimmy sshd[12245]: pam_faillock(sshd:auth): Error opening the tally file for root: No such file or directory Aug 31 15:44:53 Jimmy sshd[12026]: error: PAM: Authentication failure for root from **** Aug 31 15:44:54 Jimmy sshd[12247]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=**** user=root Aug 31 15:44:54 Jimmy sshd[12247]: pam_faillock(sshd:auth): Error opening the tally file for root: No such file or directory Aug 31 15:44:56 Jimmy sshd[12026]: error: PAM: Authentication failure for root from **** Aug 31 15:44:56 Jimmy sshd[12248]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=**** user=root Aug 31 15:44:56 Jimmy sshd[12248]: pam_faillock(sshd:auth): Error opening the tally file for root: No such file or directory Aug 31 15:44:58 Jimmy sshd[12026]: error: PAM: Authentication failure for root from **** Aug 31 15:44:58 Jimmy sshd[12026]: Received disconnect from **** port 19854:11: [preauth] Aug 31 15:44:58 Jimmy sshd[12026]: Disconnected from authenticating user root **** port 19854 [preauth] Aug 31 15:45:07 Jimmy sshd[11912]: Received disconnect from 81.28.198.29 port 50547:11: disconnected by user Aug 31 15:45:07 Jimmy sshd[11912]: Disconnected from user my_user 81.28.198.29 port 50547 Aug 31 15:45:07 Jimmy sshd[11910]: pam_unix(sshd:session): session closed for user my_user Aug 31 15:45:07 Jimmy kernel: elogind-daemon[20296]: Removed session c56. Aug 31 15:45:13 Jimmy sshd[12253]: Accepted publickey for my_user from **** port 50605 ssh2: RSA SHA256:**** Aug 31 15:45:13 Jimmy kernel: elogind-daemon[20296]: Existing logind session ID 1 used by new audit session, ignoring. Aug 31 15:45:13 Jimmy kernel: elogind-daemon[20296]: New session c57 of user my_user. Aug 31 15:45:13 Jimmy sshd[12253]: pam_unix(sshd:session): session opened for user my_user(uid=1000) by (uid=0) 1 Answer
on the remote server "X11Forwarding" must be set to "yes" in the sshd config (/etc/ssh/sshd_config). you don't have to change ssh client config (/etc/ssh/ssh_config) on your client if you use ssh -X
parameters at the ssh command overide defaults from the ssh client config (/etc/ssh/ssh_config) at your local maschine. pay attention to ssh_config vs. sshd_config -and- client vs. server. sshd could be installed on your local maschine too, but client and server only means: one side starts the concection whereas the other accepts connections (while listing).
after successfully login via ssh the DISPLAY variable should be set to something like localhost:10.0 otherwise X11 forwarding won't work.
hint: if you are connecting to a local server (on LAN) you could skip ssh X11 tunneling and simply do export DISPLAY=<clientIP>:0 on the server and issue an "xhost +<serverIPorFQDN>" on your client. this works by far faster than tunneling X through SSH.
