I start receiving the TCP_MISS/500: 1273224302.686 83 xxx.xxx.xxx.xxx TCP_MISS/500 539 GET http://domain.com/url - FIRST_UP_PARENT/kallisto text/html How can I prevent this error? The cache_peer is working quite well. If I request the site without using squid I don't receive any errors. my squid.conf --snip http_port 80 accel defaultsite=domain.com vhost cache_peer xxx.xxx.xxx.xxx parent 80 0 no-query originserver name=kallisto access_log /var/log/squid/access.log #cache_log /var/log/squid/cache.log #cache_store_log /var/log/squid/store.log #ACL acl all src 0.0.0.0/0.0.0.0 acl our_sites dstdom_regex .*domain.com.* allways_direct allow our_sites http_access allow our_sites cache_peer_access kallisto allow our_sites cache_peer_access kallisto deny all --snap - daniel