If you are using Cygwin to get a display server for your Oracle GUI-driven installations or tools like dbca, asmca (as I do from time to time), you can encounter annoying problem with X11 forwarding.
I had set as always those setting on the server in /etc/ssh/sshd_config
X11Forwarding yes
# required if you disabled ipv6
AddressFamily inet
Trying to connect to the server with X11 forwarding I got the error below:
$ ssh -X oracle@db1.dba24.pl
oracle@db1.dba24.pl’s password:
Warning: untrusted X11 forwarding setup failed: xauth key data not generated
xclock doesn’t work, Let’s check if the display has been set properly
[oracle@db1.dba24.pl ~]$ echo $DISPLAYnothing returned here
I was stuck – it was working for months, but found that note:
http://x.cygwin.com/docs/faq/cygwin-x-faq.html
ssh -X now says “Warning: untrusted X11 forwarding setup failed: xauth key data not generated”
See Q: 6.1. and following. See point 3 in this mail. Use ssh -Y.
Technical details: ssh tried to run xauth generate to create a untrusted cookie for the session, which failed because the server isn’t compiled with the XCSECURITY extension built-in. Since OpenSSH 7.2p1, ssh does not fallback to trusted forwarding, so no X11 forwarding is setup.
Let’s test -Y
$ ssh -X -Y oracle@db1.dba24.pl
oracle@db1.dba24.pl’s password:
Last login: Tue Mar 22 16:22:57 2016 from cygwin.dba24.pl[oracle@db1.dba24.pl ~]$
Now it works, xclock displays on my windows terminal.
Check DISPLAY just because I am curious:
localhost:10.0
I hope it saves your time. enjoy!!
About the author
Maciej Tokar
An Oracle technology geek and crazy long distance runner, DBA24 Owner
Senior Oracle DBA / Consultant / [OCP10g, OCP12c, OCE RAC 10g] / [experience: 9y+]
Currently working for Bluegarden (Oslo Norway) by Miratech Group
Past: Mastercard / Trevica by Britenet, Citi International PLC, PZU
