Interestingly changing this setting and then using the "export DISPLAY" route,
solves the other problems too, so they are related to going via the ssh route 
somehow. Thanks for the workaround.

Barry Branch wrote:
> On Wed, 6 Jul 2005, Alex Finch wrote:
> 
> 
>>3) Trying to avoid the ssh tunneling route does not work at all:
>>
>>    export DISPLAY=blah:0.0
>>
>>    on blah: xhost +
>>
>>   just does not work.
>>
>>
> 
> 
> Hi,
> 
> At least for this problem you should reopen the Xserver to remote connections.
> (They are now disabled by default in RHEL4).
> 
> Edit /etc/X11/gdm/gdm.conf and change the line:
> 
> #DisallowTCP=true
> to
> DisallowTCP=false
> 
> and restart X with
> kill -HUP `cat /var/run/gdm.pid`
> 
> 
> Regards,
> Barry Branch
> 


-- 
  Alex Finch, Research Fellow, Physics Department, Lancaster University.