HTTPD-ACCELERATOR OPTIONS
httpd_accel_host virtual
httpd_accel_port 80
Pero veo que el squid 2.6 esta de esta forma:
# HTTPD-ACCELERATOR OPTIONS
# -----------------------------------------------------------------------------
# TAG: httpd_accel_no_pmtu_disc on|off
# In many setups of transparently intercepting proxies Path-MTU
# discovery can not work on traffic towards the clients. This is
# the case when the intercepting device does not fully track
# connections and fails to forward ICMP must fragment messages
# to the cache server.
#
# If you have such setup and experience that certain clients
# sporadically hang or never complete requests set this to on.
#
#Default:
# httpd_accel_no_pmtu_disc off
y no veo por ningun lado la opción para la aceleración del cache.