Unable to login with static port on xrdp

Question

I have installed xrdp on a Ubuntu mate 16.04 PC and set up xrdp on it. I would like to set a static port so that same session is always opened. But for some reason when I set a static port remote desktop fails to login.

In /etc/xrdp/xrdp.ini I set port to port=-1 for a random port and I see that port 3350 is used. Remote login works with port=-1 but when I set port to port=ask3350 or port=3350 remote login does not work any more. I have also tried other ports such as 5911, 5910 etc and none work.

With static port I get following message with remote desktop application in windows 7

started connecting
connecting to 127.0.0.1 3350
tcp connected

It seems to get stuck after tcp connected.

I used following steps to setup xrdp

Installed xrpd

Modified /etc/xrdp/startwm.sh to:

#!/bin/sh

if [ -r /etc/default/locale ]; then
  . /etc/default/locale
  export LANG LANGUAGE
fi

. /etc/X11/Xsession

mate-session 

Modified [xrdp1] in /etc/xrdp/xrdp.ini to

[xrdp1]
name=sesman-Xvnc
lib=libvnc.so
username=ask
password=ask
ip=127.0.0.1
port=ask3350

When I run netstat I can see that port 3350 is active

netstat -an | grep "LISTEN" | grep ":3350"
tcp        0      0 127.0.0.1:3350          0.0.0.0:*               LISTEN 

ps axf | grep xrdp
 1058 ?        Sl    69:09 /usr/sbin/xrdp
 1096 ?        S      0:00 /usr/sbin/xrdp-sesman
 1946 ?        S      0:00  \_ /usr/sbin/xrdp-sessvc 1949 1948    
 1953 ?        Sl     0:00      \_ xrdp-chansrv
14406 pts/8    S+     0:00      \_ grep --color=auto xrdp

Any tips on how to fix this?

Solution

Well it seems that I have found a solution.

I ran this command to see available tcp ports on PC

netstat -an | grep tcp

I could see that port 5910 was available and I set port to port=ask5910 within [xrdp1] in /etc/xrdp/xrdp.ini.

ex below,

[xrdp1]
name=sesman-Xvnc
lib=libvnc.so
username=ask
password=ask
ip=127.0.0.1
port=ask5910

After I did this then remote desktop with static port 5910 worked. Not sure why it worked now because I have tried this port before and it did not work then. I did not do any changes since but for some reason it works now.

Comments

[S4M11R]

It seems that a remote desktop connection must first be opened via random port (port=-1) and then a ESTABLISHED port can be found via netstat and then set as static port. Not sure if this is 100% correct but it worked for me. After changing port to static I opened a new connection with it and then closed the connection with the random port. This connection will be valid until PC restarts at least in my case.