[Info-vax] [7.3 VAX] XDM configuration

[Matthew R. Wilson]

On 2022-11-17, JKB <JKB at hilbert.invalid> wrote:
> 	Hello,
>
> 	I have installed DECW (with SYS$UPDATE:DECW$TAILOR.EXE) on a
> 	VAXserver (without graphic adapter) and started XDM.
>
> 	XDM seems to run:
>
> $ tcpip show service xdm
> Service             Port  Proto    Process          Address            State
>  
> XDM                  177  UDP      TCPIP$XDM        0.0.0.0             Enabled
> $
>
> 	On a remote workstation (Unix), nmap shows:
>
> ORT      STATE SERVICE
> 23/tcp    open  telnet
> 49152/tcp open  unknown

I think the XDM port 177 doesn't show up because NMAP doesn't scan for
UDP ports by default.

> 	On client side, I try to connect to this VAX with
> 	Xephyr -query fermat :1
>
> 	This last command runs fine as I can connect to another Unix station
> 	with
> 	Xephyr -query legendre :1

I have vague memories of some problems when I last tried this:

1. The old version (and perhaps current versions) of the XDM/XDMCP
implementation on VMS has trouble when you're querying it from anything
other than X server display :0. I'm not sure you'll ever get it to work
using display :1 with Xnest or Xephyr. I think you'd need to move your
native X server to something other than :0 so that you can then have
Xephyr listen on :0.

2. Current/modern versions of X11 on Linux boxes are too new for OpenVMS
7.3. I've really only had luck if I intalled a backrev version of a
Linux distribution such as RHEL/CentOS 6. 

-Matthew