[squid-users] CTRL-F5 timeout problem

Generally Squid is working fine, except that users with Internet
Explorer (seems not to be a problem in Firefox) sometimes encounter long
delays (15 minutes) when they force a refresh using CTRL-F5 and the page
is truncated when they do get it back. Sometimes the problem occurs
immediately, sometimes it may need up to 15 CTRL-f5's before it occurs.

I'm running Squid 2.5.17 on windows 2003 server with three Zopes in a
load balanced configuration using ICP:
*********snippet
acl in_knetpool dstdomain knetpool

cache_peer 10.110.7.111 parent 8001 9980 no-digest no-netdb-exchange
name=port8001
cache_peer 10.110.7.111 parent 8005 9981 no-digest no-netdb-exchange
name=port8005
cache_peer 10.110.7.111 parent 8010 9982 no-digest no-netdb-exchange
name=port8010

cache_peer_access port8001 allow in_knetpool
cache_peer_access port8005 allow in_knetpool
cache_peer_access port8010 allow in_knetpool

cache_peer_access port8001 deny all
cache_peer_access port8005 deny all
cache_peer_access port8010 deny all

# THE FOLLOWING DIRECTIVE IS NEEDED TO MAKE 'backendpool' RESOLVE TO
# THE POOL OF CACHE PEERS.
# peer balancing: uncommented next two lines
never_direct allow all
icp_access allow all
*********end snippet

The 15 minute timeframe suggested a read_timeout and reducing this
parameter to 5 minutes caused the truncated page to be returned in only
5 minutes.

Some judicial use of a packet sniffer suggested that Squid had ICP'd the
Zopes and received the page's entire HTML from a Zope (within 3 seconds)
before starting to deliver it to Internet Explorer. Partway through
sending it to IE, Squid had sent a smaller than usual (622 bytes rather
than 4150) http packet to IE (and IE had acknowledged it) and then no
further data was sent until Squid timed out (logged a httpTimeout). IE
then requested other items in the page (CSS, images etc) before
displaying a truncated page (HTML truncation matched the last content
from the small data packet sent by squid).

Does anyone know why this is happening and what I can do to fix it?
Received on Wed Jan 30 2008 - 07:06:38 MST