[lug] remote clients can't display on FC3/KRUD
rm at fabula.de
rm at fabula.de
Sun Jun 19 13:32:21 MDT 2005
On Sun, Jun 19, 2005 at 11:34:31AM -0600, D. Stimits wrote:
> rm at fabula.de wrote:
> >On Sat, Jun 18, 2005 at 11:45:00PM -0600, Michael J. Hammel wrote:
> >>On Sat, 2005-06-18 at 18:19 -0600, D. Stimits wrote:
> >>>By default the X11 servers accept only UDP connections...remote machines
> >>>use TCP. You have to turn on the TCP option in
> >>>There is a line there, DisallowTCP=true. Kind of misleading, as not
> >>>having this parameter still disallows TCP. Change it to
> >>That's the ticket. Thanks D. I can now run GIMP on the server and
> >>display it on the laptop to continue working on my next book.
> >>Woohoo! :-)
> >Just a small correction: once tcp/ip connections are disabled (as they are
> >indeed on most security aware distros) the X server only listens on a local
> >(Unix) socket (normally under /tmp/.X11-unix/....). AFAIK it's _not_
> >to use udp/ip for X connections.
> I never said udp/ip :P, just udp.
Yes, that was intentional :) My point: udp _is_ an IP protocol (unless you
show me how to create a create an udp socket that's _not_ of type PF_INET ...).
> Processes using a unix socket in one
> way or another are udp enabled, regardless of how the socket/file is
Hmm. Might it be possible that you mix up 'udp' (as of RFC768 - part of
the inet family) with 'datagram' (a socket _type_).
> X11 by nature is networked...it isn't possible to run X11
> without networking functionality, although protocols and socket details
> are flexible.
Again - depends on what you consider 'networking'. You can run X11 without any
inet capabilities in the kernel as long as PF_UNIX is supported. I'd consider
Unix sockets to be part of the interproces comunication.
On the topic of X11 over udp: somehow that seems "wrong": after all, you really don't
want to have part of your X11 event stream just disapear (not nice when some of the
password characters you typed in don't make it to the X client :-/
Also, we want those 'connection to X server borken ...' (which isn't possible with udp).
In theory it _would_ be possible to use _datagrams_ over Unix domain sockets on Linux
since, according to the docs, "... as on most Unix implementations, Unix domain datagram sock-
ets are always reliable and don't reorder datagrams". But i just checked my local box:
hobbes:~$ ps aux | grep '[X] :0'
root 3439 2.9 13.0 84504 41764 ? S< 13:24 15:23 /usr/X11R6/bin/X :0 -br -audit 0 -auth ...
ralf at hobbes:~$ lsof -p 3439
ralf at hobbes:~$ sudo lsof -p 3439 | grep /tmp/
Xorg 3439 root 4u unix 0xd220ce20 5709 /tmp/.X11-unix/X0
Xorg 3439 root 10u unix 0xd3459c40 6412 /tmp/.X11-unix/X0
Xorg 3439 root 18u unix 0xc8713200 20649 /tmp/.X11-unix/X0
Xorg 3439 root 23u unix 0xc793ecc0 21037 /tmp/.X11-unix/X0
ralf at hobbes:~$ sudo netstat -p 3439 | grep tmp/.X11-unix/
unix 3 [ ] STREAM CONNECTED 21037 3439/X /tmp/.X11-unix/X0
unix 3 [ ] STREAM CONNECTED 20649 3439/X /tmp/.X11-unix/X0
unix 3 [ ] STREAM CONNECTED 16425 3439/X /tmp/.X11-unix/X0
unix 3 [ ] STREAM CONNECTED 9654 3439/X /tmp/.X11-unix/X0
unix 3 [ ] STREAM CONNECTED 8579 3439/X /tmp/.X11-unix/X0
unix 3 [ ] STREAM CONNECTED 8550 3439/X /tmp/.X11-unix/X0
unix 3 [ ] STREAM CONNECTED 8547 3439/X /tmp/.X11-unix/X0
unix 3 [ ] STREAM CONNECTED 6412 3439/X /tmp/.X11-unix/X0
ralf at hobbes:~$
seems like the Xserver uses socket type stream.
Cheers Ralf Mattes
o D. Stimits, stimits AT comcast DOT net
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