Sample configuration for squid proxy server. Source here -> https://calomel.org/squid.html

squid.conf

#
### Calomel.org Squid  squid.conf
#
########### squid.conf ###########
#
## interface, port and proxy type
#http_port 10.10.10.1:8080 transparent
http_port 10.10.10.1:8080

## general options
cache_mgr not_to_be_disturbed
client_db on
collapsed_forwarding on
detect_broken_pconn on
dns_defnames on
dns_retransmit_interval 2 seconds
dns_timeout 5 minutes
forwarded_for off
half_closed_clients off
httpd_suppress_version_string on
ignore_unknown_nameservers on
pipeline_prefetch on
retry_on_error on
strip_query_terms off
uri_whitespace strip
visible_hostname localhost

## timeouts
forward_timeout 30 seconds
connect_timeout 30 seconds
read_timeout 30 seconds
request_timeout 30 seconds
persistent_request_timeout 1 minute
client_lifetime 20 hours

## host definitions
acl all src 0.0.0.0/0
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8

## proxy server client access
acl mynetworks src 127.0.0.0/8 10.10.10.0/28
http_access deny !mynetworks

## max connections per ip
acl maxuserconn src 127.0.0.0/8 10.0.10.0/28
acl limitusercon maxconn 500
http_access deny maxuserconn limitusercon

## disable caching
cache deny all
cache_dir null /tmp

## disable multicast icp
icp_port 0
icp_access deny all

## disable ident lookups
ident_lookup_access deny all

## no-trust for on-the-fly Content-Encoding
acl apache rep_header Server ^Apache
broken_vary_encoding allow apache

## logs
logformat combined [%tl] %>A %{Host}>h "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
access_log /var/log/squid/access.log combined
cache_store_log /var/log/squid/store.log
cache_log  /var/log/squid/cache.log
logfile_rotate 8

## support files
coredump_dir /tmp
pid_filename /var/log/squid/squid.pid

## ports allowed
acl Safe_ports port 80 443
http_access deny !Safe_ports

## ssl ports/method allowed
acl SSL_ports port 443
acl CONNECT method CONNECT
http_access deny CONNECT !SSL_ports

## protocols allowed
acl Safe_proto proto HTTP SSL
http_access deny !Safe_proto

## browsers allowed
# acl Safe_browser browser ^Mozilla/5\.0.*Firefox/2\.0\.0\.6
# http_access deny !Safe_Browser

## disable ads ( //squid_adservers.html )
# acl ads dstdom_regex "/etc/squid/ad_block.txt"
# http_access deny ads
# deny_info TCP_RESET ads

## Banned Sites
# acl Bad_Site dstdom_regex myspace.com youtube.com facebook.com 
# http_access deny Bad_Site

## redirector
# acl my_url dstdomain SITE_NAME.COM
# redirector_access allow my_url
# redirect_children 1
# redirect_rewrites_host_header off
# redirect_program /etc/squid/squid_redirector.pl

## methods allowed
acl Safe_method method CONNECT GET HEAD POST
http_access deny !Safe_method

## allow replies to client requests
http_reply_access allow all

## header re-write
# header_replace Accept */*
# header_replace Accept-Encoding gzip
# header_replace Accept-Language en
header_replace User-Agent OurBrowser/1.0 (Some Name)

## header list ( DENY all - ALLOW listed )
header_access Accept allow all
header_access Accept-Encoding allow all
header_access Accept-Language allow all
header_access Authorization allow all
header_access Cache-Control allow all
header_access Content-Disposition allow all
header_access Content-Encoding allow all
header_access Content-Length allow all
header_access Content-Location allow all
header_access Content-Range allow all
header_access Content-Type allow all
header_access Cookie allow all
header_access Expires allow all
header_access Host allow all
header_access If-Modified-Since allow all
header_access Location allow all
header_access Range allow all
header_access Referer allow all
header_access Set-Cookie allow all
header_access WWW-Authenticate allow all
header_access All deny all

##########  END  ###########

squidman template

# ----------------------------------------------------------------------
# WARNING - do not edit this template unless you know what you are doing
# ----------------------------------------------------------------------

# the parent cache
cache_peer %PARENTPROXY% parent %PARENTPORT% 7 no-query no-digest no-netdb-exchange default


# performance options
pipeline_prefetch %PIPELINE_PREFETCH%
cache_miss_revalidate %CACHE_MISS_REVALIDATE%
read_ahead_gap %READ_AHEAD_GAP%
cache_replacement_policy %CACHE_REPLACEMENT_POLICY%
memory_replacement_policy %MEMORY_REPLACEMENT_POLICY%


# disk and memory cache settings
cache_dir ufs %CACHEDIR% %CACHESIZE% 16 256
maximum_object_size %MAXOBJECTSIZE%
cache_mem %MEMCACHESIZE%
maximum_object_size_in_memory %MEMMAXOBJECTSIZE%


# store coredumps in the first cache dir
coredump_dir %CACHEDIR%


# the hostname squid displays in error messages
visible_hostname %VISIBLEHOSTNAME%


# log & process ID file details
cache_access_log stdio:%ACCESSLOG%
cache_store_log stdio:%STORELOG%
cache_log %CACHELOG%
pid_filename %PIDFILE%


# Squid listening port
http_port %PORT%


# Access Control lists
acl SSL_ports port 443
acl Safe_ports port 80		# http
acl Safe_ports port 21		# ftp
acl Safe_ports port 443		# https
acl Safe_ports port 70		# gopher
acl Safe_ports port 210		# wais
acl Safe_ports port 1025-65535	# unregistered ports
acl Safe_ports port 280		# http-mgmt
acl Safe_ports port 488		# gss-http
acl Safe_ports port 591		# filemaker
acl Safe_ports port 777		# multiling http
acl CONNECT method CONNECT
%ALLOWEDHOSTS%
%DIRECTHOSTS%


# Only allow cachemgr access from localhost
http_access allow localhost manager 
http_access deny manager


# Deny requests to certain unsafe ports
http_access deny !Safe_ports


# Deny CONNECT to other than secure SSL ports
http_access deny CONNECT !SSL_ports


# protect web apps running on the proxy host from external users
http_access deny to_localhost


# rules for client access go here
http_access allow localhost
%HTTPACCESSALLOWED%


# after allowed hosts, deny all other access to this proxy
# don't list any other access settings below this point
http_access deny all


# specify which hosts have direct access (bypassing the parent proxy)
%ALWAYSDIRECT%
always_direct deny all


# refresh patterns (squid-recommended)
refresh_pattern ^ftp:		1440	20%	10080
refresh_pattern ^gopher:	1440	0%	1440
refresh_pattern -i (/cgi-bin/|\?) 0	0%	0
refresh_pattern .		0	20%	4320

# anonymize
via off
forwarded_for off