[SunHELP] Inetd blacklist file?

[Adam Victor Reed]

My family mail server is an old Sparcstation 5 with Solaris 8
(including sendmail) plus qpopper etc. Yesterday inetd began to deny
access to the qpopper (pop3) port 110 with the message

telnet: Unable to connect to remote host: Connection refused

even though /etc/inetd.conf and /etc/services are unchanged (I checked
with sum). The entry in /etc/inetd.conf is

pop3 stream tcp nowait.600 root /usr/local/lib/popper qpopper -d -s -c -R

and in /etc/services

pop3            110/tcp            # Post Office Protocol - Version 3

I know that this means that qpopper is never started - if inetd
started qpopper and qpopper quit, the diagnostic would say "closed"
rather than "refused".

Restarting inetd or re-booting the server have no effect on this
response, even though everything else on the server works normally,
mail is received and forwarded correctly etc.

My best guess is that inetd monitors the return codes of its children,
and if a child crashes then its port is blocked until the sysadmin
does something - but what? How does inetd maintain its list of blocked
ports?

My second-best guess is that some other process has started listening
to port 110 (so inetd is blocked from this port) without accepting
connections. How can I find out what processes have opened what ports?
Is there a shell command that will give me a list? Is there an option
to inetd for logging the problems encountered in attempting to listen
on ports?

I would be grateful for help with the above, or for insight on any
other possible causes of this problem.
-- 
				Adam Reed
				areed2 at calstatela.edu
				 
Context matters. Seldom does *anything* have only one cause.