Can't use XDMCP, "winProcEstablishConnection - ProcEstablishConnection failed, bailing" shows in log

[Jon TURNEY]

> On Wed, Feb 9, 2011 at 6:37 PM, Jon TURNEY <jon.turney@dronecode.org.uk> wrote:
>> I wonder if you could send me privately the Wireshark .pcap files for these
>> traces, I'd like to examine them further.

On 11/02/2011 18:45, Alexander Pokluda wrote:
> I've attached a zip archive containing a number of files. The pcap
> files were created by running Wireshark on both ends while attempting
> to establish an XDMCP session between the hosts. Here is a description
> of the files:

Thanks very much for these.

Unfortunately, these seem to show that the XDMCP request packet leaves the
machine running XWin, but doesn't arrive at the VM.

I've no idea why that might be, but that suggests to me they are being dropped
in your network, or between the host running the VM and the guest VM?

> After I took the above screenshot, I realized that I had a VirtualBox
> adapter with IPv6 enabled, so I disabled the VirtualBox adapter and
> ran the XWin command again, capturing packets on both ends. These
> files contain the captured packets. One interesting thing to note is
> that the request packet sent from XWin contains my IPv4 address
> converted to an IPv6 address even when IPv6 is disabled on my physical
> adapter.

These look like link-local IPv6 addresses (prefix fe80::) to me, rather than
IPv6 mapped IPv4 addresses (prefix ::ffff:)?

However, this does look like a bug (or at least the code not doing what it
says it does): when the -from option is used, the XDMCP request contains the
specified address *and* any other addresses we have of different address
families to the specified address (e.g., if we specify an IPv4 address, we get
only that IPv4 address, but all the IPv6 addresses as well)

I've built a snapshot which contains a change which modifies the behaviour of
-from so only the specified address is included in the XDMCP request, and
uploaded it at [1].

With this change, the XDMCP request sent by XWin and XMing should be nearly
identical. Perhaps you could try that out and see if that makes a difference.

ftp://cygwin.com/pub/cygwinx/XWin.20110214-git-d593beaadac1371e.exe.bz2

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