How to Configure Squid Proxy for LDAP Authentication on CentOS 6.2 using squid_ldap_auth

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In this post i will show on how to configure squid proxy server to go through 389 LDAP authentication on linux CentOS 6.2 server. This authentication is using squid_ldap_auth module in that come with squid proxy. Assumed that you have 389 Ldap Directory server and Squid proxy configured. Squid service plays two main roles which mainly act as a caching proxy server between the user and the web. 389 Directory Server is an enterprise-class open source LDAP server for Linux.

Some informations regarding proxy server and ldap server.
Proxy server : 192.168.1.44 proxy.ehowstuff.local
LDAP server : 192.168.1.48 ldap.ehowstuff.local

Prerequisites :
How to Install and Configure Squid Proxy Server on CentOS 6.2
How to Restrict Web Access By Time Using Squid Proxy Server on CentOS 6.2
How to Install 389 Directory Server on CentOS 6.2
How to Setup and Configure 389 Directory Server on CentOS 6.2

Add in this lines on your squid.conf file :

auth_param basic program /usr/lib/squid/squid_ldap_auth -b "dc=ehowstuff,dc=local" -f "uid=%s" -h ldap.ehowstuff.local
acl ldapauth proxy_auth REQUIRED
http_access allow ldapauth
http_access deny all

“http_access deny all” is optional, it’s depend on your configuration.

Open squid.conf file and modify as below :

..
..
..
acl localnet src 172.16.0.0/12  # RFC1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
acl localnet src fc00::/7       # RFC 4193 local private network range
acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines
acl ehowstuff.com src 192.168.1.0/24    # Your internal network

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


#Specifies the base DN for LDAP authentication :
auth_param basic program /usr/lib/squid/squid_ldap_auth -b "dc=ehowstuff,dc=local" -f "uid=%s" -h ldap.ehowstuff.local
acl ldapauth proxy_auth REQUIRED
http_access allow ldapauth


#Add this at the bottom of the ACL Section
#
acl surfing_hours time M T W H F 17:00-24:00
acl Bad_Websites  dstdomain "/etc/squid/web/Bad_Websites.squid"

#
# Recommended minimum Access Permission configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
http_access deny manager

# Only allow cachemgr access from ehowstuff.com
http_access allow ehowstuff.com surfing_hours !Bad_Websites
http_access deny Bad_Websites
http_access deny ehowstuff.com
..
..
..

Proxy ip : 192.168.1.44
Domain/Hostname : proxy.ehowstuff.local
Port : 3128

Browser that was configured with proxy setting will prompt as below :
squid

Complete Squid configuration :

#
# Recommended minimum configuration:
#
acl manager proto cache_object
acl localhost src 127.0.0.1/32 ::1
acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1

# Example rule allowing access from your local networks.
# Adapt to list your (internal) IP networks from where browsing
# should be allowed
acl localnet src 10.0.0.0/8     # RFC1918 possible internal network
acl localnet src 172.16.0.0/12  # RFC1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
acl localnet src fc00::/7       # RFC 4193 local private network range
acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines
acl ehowstuff.com src 192.168.1.0/24    # Your internal network

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


#Specifies the base DN for LDAP authentication :
auth_param basic program /usr/lib/squid/squid_ldap_auth -b "dc=ehowstuff,dc=local" -f "uid=%s" -h ldap.ehowstuff.local
acl ldapauth proxy_auth REQUIRED
http_access allow ldapauth


#Add this at the bottom of the ACL Section
#
acl surfing_hours time M T W H F 17:00-24:00
acl Bad_Websites  dstdomain "/etc/squid/web/Bad_Websites.squid"

#
# Recommended minimum Access Permission configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
http_access deny manager

# Only allow cachemgr access from ehowstuff.com
http_access allow ehowstuff.com surfing_hours !Bad_Websites
http_access deny Bad_Websites
http_access deny ehowstuff.com



# 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

# We strongly recommend the following be uncommented to protect innocent
# web applications running on the proxy server who think the only
# one who can access services on "localhost" is a local user
#http_access deny to_localhost

#
# INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
#

# Example rule allowing access from your local networks.
# Adapt localnet in the ACL section to list your (internal) IP networks
# from where browsing should be allowed
#http_access allow localnet
http_access allow localhost

# And finally deny all other access to this proxy
http_access deny all

# Squid normally listens to port 3128
http_port 3128

# We recommend you to use at least the following line.
hierarchy_stoplist cgi-bin ?

# Uncomment and adjust the following to add a disk cache directory.
#cache_dir ufs /var/spool/squid 100 16 256

# Leave coredumps in the first cache dir
coredump_dir /var/spool/squid

# Add any of your own refresh_pattern entries above these.
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

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