Re: [lvs-users] xdmcp question

To: " users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] xdmcp question
From: Joseph Mack NA3T <jmack@xxxxxxxx>
Date: Fri, 18 Jan 2008 12:39:05 -0800 (PST)
On Fri, 18 Jan 2008, chris barry wrote:

>> I assume you've read my attempts at xdmcp in the HOWTO. It
>> looks like you got further than me. If so, can you send me
>> (off-line) what you did, so I can update the HOWTO.
> Yes.

thanks got it. I was hoping for a verbal description of how 
to get it going :-)

Can you run your setup without iptables rules. You shouldn't 
need them to set up any standard LVS, and they'll only 
confuse the picture till you get it running.

>> are you then connecting directly to the realserver by
>> chance.
> That's what I'm not sure of. It seems so, however the clients cannot
> route to the real servers on their own,

don't trust ping on this. You'll need tcpdump

> so the packets must be somehow going around the lvs stuff. 
> I think it's a FWM issue too. I'll need to do some more 
> captures to understand what port ranges are being used. 
> From what you say in the howto, basically you hook up on 
> 177, but after that it's not used anymore. the RS and 
> client must negotiate another port to use.

If X steps in next, there'll be a whole heap of ports at 
6000 (I think). Look at the writeup for ftp, identd and rsh 
for the problems that LVS gets into when the realserver 
negotiates ports with the client that the director doesn't 
know about.

Can you tunnel the X through ssh?

>> I think you're going to have to be the one to figure it 
>> out. If X is involved as well, there's many ports 
>> involved - you may have to group them with fwmarks.
> yep. I think you're right. I'll send my ipvsadm and 
> iptables files your way for perusal.

Can you try a more minimal setup. You have enough lines in 
your ipvsadm output to be an X-server farm


Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at
Homepage It's GNU/Linux!

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