#884945 xdm: opens TCP port for (XDMCP?) LISTEN

Package:
xdm
Source:
xdm
Description:
X display manager
Submitter:
Paul Szabo
Date:
2017-12-21 20:45:04 UTC
Severity:
normal
#884945#5
Date:
2017-12-21 20:36:07 UTC
From:
To:
Dear Maintainer,

When configured for XDMCP (to LISTEN on UDP port 177), xdm also opens
a random, high-numbered TCP (tcp6, IPv6) port to LISTEN. Currently my
xdm shows:

root@p639:~# netstat -anp | grep xdm
tcp6       0      0 :::51359                :::*                    LISTEN      2471/xdm
udp        0      0 0.0.0.0:177             0.0.0.0:*                           2471/xdm
unix  3      [ ]         STREAM     CONNECTED     4867     2471/xdm
root@p639:~# lsof -p 2471 | grep -E -i 'udp|tcp|unix'
xdm     2471 root    1u  unix 0xffff880118ee7480      0t0    4867 type=STREAM
xdm     2471 root    3u  IPv6               8097      0t0     TCP *:51359 (LISTEN)
xdm     2471 root    4u  IPv4               6954      0t0     UDP *:xdmcp
root@p639:~#

I wonder whether this is a recurrence of bug#239341.

Please let me know if I should investigate further.

Thanks, Paul

Paul Szabo   psz@maths.usyd.edu.au   http://www.maths.usyd.edu.au/u/psz/
School of Mathematics and Statistics   University of Sydney    Australia