еще раз прочитать внимательно комментарий в squid.conf
# NETWORK OPTIONS
# -----------------------------------------------------------------------------
# TAG: http_port
# Usage: port
# hostname:port
# 1.2.3.4:port
#
# The socket addresses where Squid will listen for HTTP client
# requests. You may specify multiple socket addresses.
# There are three forms: port alone, hostname with port, and
# IP address with port. If you specify a hostname or IP
# address, then Squid binds the socket to that specific
# address. This replaces the old 'tcp_incoming_address'
# option. Most likely, you do not need to bind to a specific
# address, so you can use the port number alone.
#
# The default port number is 3128.
#
# If you are running Squid in accelerator mode, then you
# probably want to listen on port 80 also, or instead.
#
# The -a command line option will override the *first* port
# number listed here. That option will NOT override an IP
# address, however.
#
# You may specify multiple socket addresses on multiple lines.
#
# If you run Squid on a dual-homed machine with an internal
# and an external interface then we recommend you to specify the
# internal address:port in http_port. This way Squid will only be
# visible on the internal address.
#
#Default:
# http_port 3128