Xinetd and file descriptor limits?

I am experiencing an error condition involving use of xinetd and apparent
file descriptor limits.  To summarize, when I start xinetd and parse
numerous service files (as found in /etc/xinetd.d/), I receive the
following error in the syslog:

---<snip>---
Jan  4 14:43:03 estes xinetd[1852]: Service sserver-4121 disabled because
of lack of file descriptors
Jan  4 14:43:03 estes xinetd[1852]: xinetd Version 2.3.12 started with
libwrap loadavg options compiled in.
Jan  4 14:43:03 estes xinetd[1852]: Started working: 1016 available services
---<snip>---

I am staring numerous sservers (an ssl'ified version of pserver, Corey
Minyard's version) - in fact, over a thousand of these alone.
Corresponding lines do exist in /etc/services (one per sserver port).  The
number in the service name relates to the port it listens on.  I begin
assigning sserver ports at 3025, and climb from there.  Ports up to 4020
listen properly.  I have a minimal set of services running in the
privileged port space, among them ssh, httpd, httpsd, mysql, postgres and
portsentry.

System particulars are:

Kernel .......... 2.4.18-14 (Redhat 8 base distro)
xinetd........... 2.3.12 compiled with libwrap & loadavg
/proc/sys/fs/file-max ............. various settings above 1024
ulimit -n ........ various settings well above 1024 (once at 200000)
Web server ........ Apache 1.3.9

I have also placed in the xinted startup script two 'ulimit' statements
that are intended to increase the fd limit for the user that starts
xinetd.  The statements are at the top of the script before any other
action takes place.  Those statements are:

ulimit -Hn 65535
ulimit -Sn 8192

I have experienced this error on two separate servers, each running
originally identical configurations, and then tweaking on one them
versions of xinetd, the kernel and apache such that the error presents in
the very latest of all three:

xinetd  (originally 2.3.10) .... 2.3.12
kernel  (originally 2.4.20-8) ...2.6.0
apache  (originally 1.3.9) ......2.0.40

I am running all these commands as root.  My apache user is non-root.  I
have also run xinetd with '-d', but haven't been able to capture the
output.  It seems that the '-d' overrides atemmpts to redirect to a log.
How is the output of '-d' captured for review?

At the time the error presents, a 'lsof | wc -l' shows 5653 lines of
output.  I believe this maps directly to the total of both open ports and
files, right?  That is well below the value returned from 'ulimit -n', as
well as below the value in /proc/sys/fs/file-max.

I suspect I am hitting the system or user default of 1024 file
descriptors, but I am curious why that number (1024) doesn't quite match
the number of services successfully started, 1016.  Are these in fact
related?  Is the error message believed to be informative?  I am stumped
as to what else to review.  Is there another setting that controls this &
I've simply missed it?

Thanks for any assistance.

-- 
John Minnihan
Founder & Chief Architect
https://www.freepository.com
Free software development tools since 1999