It all seems so easy.. and then it isn’t easy.. and then you realize you have no effing idea how the X Window system works.
[bitwiseoperator@Fedora22 ~]$ ssh -f aix71 xterm bitwiseoperator@aix71's password: [bitwiseoperator@Fedora22 ~]$ xterm Xt error: Can't open display: xterm: DISPLAY is not set
So, here’s a shortcut: for the one other person on the planet (maybe there’s one?) who has to forward X11 content from AIX 7.1 to a connecting Fedora 22 system, you need to explicitly enable X11 forwarding in the options specified for the connection with the command line option “-o”:
[bitwiseoperator@Fedora22 ~]$ ssh -f -o FORWARDX11="yes" aix71 xterm bitwiseoperator@aix71's password: [bitwiseoperator@Fedora22 ~]$ 1356-364 /usr/bin/X11/xauth: creating new authority file /home/bitwiseoperator/.Xauthority [bitwiseoperator@Fedora22 ~]$
And it works! A little xterm pops right up.
This guy writes a good article, but his troubleshooting steps didn’t anticipate that one. Maybe people are just suspected to know if their ssh client software requires the explicit declaration of X11 forwarding as an option on the command line, but I rarely do it, myself; I’m usually all CLI all the time. When I have performed X11 forwarding in the past, it’s been through PuTTy’s simple GUI, so I remained ignorant of the relevant command line syntax (the greatest UNIX sin there is..). It’s kind of embarrassing not to reflexively know how to do something so simple.
So now you know, too!