ERR_CANNOT_FETCH on DU 4.0 and Squid 1.1.8

I receive intermittently the following message. I am running Digital Unix 4.0
and Squid 1.1.8.

The cache 'recovers' and answers queries but the cache process does not restart.
The following error was encountered:

     Unable to Retrieve

The system returned:

    No peers to query and the host is beyond your firewall.

The cache administrator may need to double-check the cache configuration.

This means that:

    The requested URL can not currently be retrieved.

The access.log shows for example

ERR_CANNOT_FETCH/400 941 GET http://www.baynetworks.com/ - NO_DIRECT_FAIL/www.ba
ynetworks.com but later shows

TCP_MISS/200 4780 GET http://www.baynetworks.com/ - SINGLE_PARENT/146.80.9.65 te
xt/html

kill -1 of the squid process appears to cure it for a bit. My assumption is
 as the network connection between the cache and the firewall is not broken, the
 firewall correctly connects and it is an intermittent problem that this is a
squid and/or Digital Unix problem. Does anyone have any ideas ?

Dave
------

Dave Hartley Tel No: +44-1684-896000
DRA Malvern
St. Andrews Road Fax No: +44-1684-895700
Malvern
WR14 3PS email: hartley@dra.hmg.gb
UK
Received on Mon Apr 21 1997 - 03:37:12 MDT