NNTP periodic failures on ISC UNIX

[Paul Gillingwater]

We have a problem with our NNTP, and would appreciate any helpful
suggestions.

Here's our configuration:

386/33MHz with ISC 2.2.1, running TCP/IP 1.2 on a WD 1003E LAN card.
We're connected via a PCRouter (software running on another PC) to a
local University Internet node, where we receive mail and news via
SMTP and NNTP.  We have 10 Mb of RAM.

We're using NNTP version 1.5.11 (with patches for ISC UNIX).

The problem is that two or three times a day, the NNTP appears to
lock up.  This also causes mail to stop, so it seems to be a problem
that restricts a resource used by both SMTP and NNTP (perhaps
streams buffers?)

We've tried shutting down the LAN, then restarting it by changing the
init level, but this does not seem to work.  We know that the
PCRouter is fine, because we can still TELNET or FTP over the LAN
(sometimes).  We can usually PING the PCRouter successfully too.
This has meant that the only way we can restart the connection is to
do a complete powerdown and reboot.

Obviously, this isn't very pleasant.

Can anyone (especially ISC support) suggest a possible cause for
this, and perhaps a fix?  For example, how can we find out if there
is a memory leak, or perhaps a loss of streams buffers?  Is there
some way we can enable NNTP debug logging to trace where it fails?

Another symptom is that there seem to be multiple NNTP processes
left hanging around (we have a housekeeping script which kills these
off from time to time).  If they're not killed cleanly, perhaps some
resource is being lost.  This seems to be a result of occasional
loss of connection to our feed.  The active NNTP process stops, but
doesn't go away.  When more news comes through, a new NNTP process
is started, but the old one doesn't go away.

Here's a netstat -a:

Active Internet connections (including servers)
Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp        0   2259  192.100.53.17.nntp     130.195.5.20.6750      CLOSED
tcp        0      0  *.smtp                 *.*                    LISTEN
tcp        0      0  *.time                 *.*                    LISTEN
tcp        0      0  *.daytime              *.*                    LISTEN
tcp        0      0  *.chargen              *.*                    LISTEN
tcp        0      0  *.discard              *.*                    LISTEN
tcp        0      0  *.echo                 *.*                    LISTEN
tcp        0      0  *.domain               *.*                    LISTEN
tcp        0      0  *.finger               *.*                    LISTEN
tcp        0      0  *.nntp                 *.*                    LISTEN
tcp        0      0  *.exec                 *.*                    LISTEN
tcp        0      0  *.login                *.*                    LISTEN
tcp        0      0  *.shell                *.*                    LISTEN
tcp        0      0  *.telnet               *.*                    LISTEN
tcp        0      0  *.ftp                  *.*                    LISTEN
tcp        0      0  *.*                    *.*                    CLOSED
udp        0      0  *.1225                 *.*                   
udp        0      0  *.1030                 *.*                   
udp        0      0  *.1027                 *.*                   
udp        0      0  192.100.53.17.domain   *.*                   
udp        0      0  127.0.0.1.domain       *.*                   
udp        0      0  *.domain               *.*                   
udp        0      0  *.ntalk                *.*                   
udp        0      0  *.1025                 *.*                   
udp        0      0  *.1024                 *.*                   
udp        0      0  *.syslog               *.*                   
udp        0      0  *.*                    *.*                   

Any help would be gratefully appreciated.
-- 
Paul Gillingwater, paul at actrix.gen.nz