Lost network XDMCP access

[John Collier]

I have two Linux boxes at home that I have been using Reflection X to connect to via my M$ Windoze machines. One of the Linux boxes is Fedora Core 3 (i386), the other is Fedora Core 4 (x86_64).

Recently, I have lost the ability to connect to either box via Reflextion X. I have checked the settings on both of the FC boxes and nothing appears to have changed. I know that I changed nothing in the Reflextion program.

When I bring up the reflection software and ask it to do an XDMCP broadcast, it returns the listing for both of the FC boxes, but when I go to connect I get an error telling me that it can't find the server that I selected from the menu that it just provided.

I did not install a firewall on either of the FC boxes since they are both on a private, secure LAN that is already protected from the public.

Have there been some recent changes that anybody knows of that could make this happen? What can I do and/or check to get this resolved?

I hate to sound pushy, but my wife blew up her computer and will now have to access an account on my FC4 box via a Reflection session from my Daughter's Windoze machine and she needs to do this quickly due to business.

Please tell me that one of you can provide an answer...


As in all my threads, points to be awarded after solution found so that it can be done fairly. But I PROMISE points to all who respond.


Thanks!!

[Steven E. Protter]

If this were a business network,I'd say the cause is because someone implemented VLAN on the network. Broadcast XDMCP won't work across VLANS.

If you did this at home, then try direct access using reflections and the IP address of the workstation.

Direct IP connection DOES work across VLAN so that my first guess.

SEP

[John Collier]

Steve,

Thanks for the suggestion, but I'm affraid it will take more than that to make this work. I just tried your suggestion and I still get the same error.

BTW, the exact error is:

Your XDMXP connection timed out - make sure that the hosts on your network are running XDM programs. [RX2102]

Now, logging directly from one FC box to the other using the XDMCP chooser at the logon screen works and I have rechecked the configs to make sure that I didn't do anything that I know of to be stupid on the Linux boxes.

What is the next step?

[Steven E. Protter]

Make sure the font server is still running on the host.

/etc/init.d/xfs

SEP

[John Collier]

According to a quick grep through the ps list, it would seem it is:

xfs 2341 1 0 Sep10 ? 00:00:00 xfs -droppriv -daemon

[Steven E. Protter]

I agree xfs is probably running.

service xfs status

Also, HOW ABOUT SOME HELP HERE Linux folk?

Next step.

service iptables stop

Try it again.

SEP

[John Collier]

Using the command you suggest:

# service xfs status
xfs (pid 2341) is running...

Verified running.

Same concept with iptables:

# service iptables status
Firewall is stopped.


So, xfs is running and firewall is down but I still have the error mentioned above. Hmmmmm...

I am stumped.

Anybody else?

[RAC_1]

Anything is syslog??-/var/log/messages
or in /var/dt/Xerrors??

Is dtlogin running??

[Rajesh SB · Accepted solution]

Hi,

Here is the helpful thread for your problem.

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=624254

Let me know, which Display manager are you using, whether gdm or kdm/xdm.
Ensure the XDMCP is enabled for connecting.


Regards,
Rajesh

[Ivan Ferreira]

Run gdmsetup again and verify/recheck your XDMCP configuration.

Or post the configuration of /etc/X11/gdm/gdm.conf, section [xdmcp].

Run netstat when you try to connect from your windows client, and see if you get an SYN_RCV for that client.

[John Collier]

Rac,

Not sure what to search for exactly in the logs (/var/log/messages). There is much info there, but a grep for xdmcp (either case) does not do the trick. Mind pointing a better string out to search for?

As far as the Xerrors file, I do not seem to have one on my system. It was not at the path you had listed and a quick find through the entire file system returned no results.


Rajesh,

I thank you for the link to the other thread. After reading through it and trying some of the suggestions, I think I may have found something of interest.

# netstat -an | grep 177
udp 0 0 0.0.0.0:177 0.0.0.0:*

Does this mean that it is not listening on the correct port? If so, where do I go to resolve this? I have never come across anything like this before.

The only thing that I have seen that might do it for me is in the etc/X11/gdm/gdm.conf file under the section that Ivan is suggesting.

Out of that [xdmcp] section, the important areas would seem to be:

[xdmcp]
Enable=true

All the rest is simply comments. In the comments, they have a port statement that is also commented out which reads "Port=177". Should I uncomment that to force it to listen on port 177?

I am tempted to try it anyway, but I thought I would look for input prior to doing so since the Gurus are now looking into this for me.


BTW, thanks everybody!

[John Collier]

Well, even though I never got the clarification on the port configuration issue from my last post, I did some reading and finally decided that it could not hurt to try it out.

I am glad to report that simply removinf the # sign in the config file as mentioned above was all that it took to get the issue to go away. I can now use Reflection X to connect to my FC boxes from my only remaining Windoze machine.

Thanks for pointing me in the right direction!