Xwindow XDMCP DISPLAY issue

English Network/Internet
#1

Greetings,

I’m encountering a strange issue with remote xwindow XDMCP sessions.

/etc/hosts on server1 and server2:
192.168.1.88 SERVER1.MAGRO SERVER1
192.168.1.89 SERVER2.MAGRO SERVER2

server1 is an openSUSE-42.1
server2 is an openSUSE-13.2

On server1 I want to start an Xserver at vt8 and I type

server1@root:~ > /usr/bin/Xorg :8.0 vt8 -query server2

The display switches to an all black vt8.
Switching back to vt7 I see the following lines (after ~60sec):
…
Fatal server error:
(EE) XDMCP fatal error: Session failed Session 34272013 failed for displa
(EE)
…
Note: ‘displa’ apparently is truncated.

Then on server2, I find the following lines with journalctl:

…
Nov 18 12:00:33 SERVER2 kdm[27950]: localhost:8[27950]: Cannot connect to localhost:8, giving up
Nov 18 12:00:33 SERVER2 kdm[1113]: Display localhost:8 cannot be opened
…
On server2 the display should be SERVER1.MAGRO:8.

It works the other way round, that is I get an Xserver on vt8 with
server2@root:~ > /usr/bin/Xorg :8.0 vt8 -query server1
an can login to an Xsession.
echo $DISPLAY shows
SERVER2.MAGRO:8

Where and when is the variable DISPLAY set?
In /etc I did a ‘grep -r DISPLAY= *’ but did not recognize anything suitable.

Thanks for reading and any hints.
Wolf

#2

I’m going to hazard a wild guess that something is mapping incorrectly to the localhost interface instead of your remote network interface.

To verify,
Try editing your hosts file (can be done in YAST) to re-map localhost to your network address 192.168.1.89 instead of 127.0.0.1 (or 127.0.0.2 sometimes)

TSU

#3

Xorg apparently uses the first network interface made available during boot, which is the second network interface.

With

ifdown br1
ifup   br1

in after.local I force br1 being placed after br0 and it works.
ifstatus br0; ifstatus br1

br0             up
      link:     #5, state up, mtu 1500
      ...
br1             up
      link:     #6, state up, mtu 1500
      ...

shows that br1 with link #6 is placed after br0.

Issue solved.

#4

Cool. Thanks for sharing the solution. Didn’t know something stupid like this was possible :slight_smile: