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Squid with authentication on Centos 6

How to install Squid with authentication on Centos 6

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[NOTE: According to our AUP/TOS you can use only private proxy servers with authentication.]

 

There are several authentication helpers, squid can work with. In this guide we will set up ncsa_auth helper.
Install squid if you haven't it installed yet:

yum install squid

If there is any problem with installing squid - install EPEL repo:

wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm

Enable the remi repository by opening file /etc/yum.repos.d/remi.repo and set enabled=1

name=Les RPM de remi pour Enterprise Linux $releasever - $basearch
#baseurl=http://rpms.famillecollet.com/enterprise/$releasever/remi/$basearch/
mirrorlist=http://rpms.famillecollet.com/enterprise/$releasever/remi/mirror
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi
failovermethod=priority

Now when EPEL is installed you can install squid as shown above.
Before setting up the authentication, test basic squid functionality. It has to work without requiring authorization.
Create user:

htpasswd -c /etc/squid/passwd user1

This command creates file passwd. In this file will be stored NCSA users and passwords.
Output:

New password:
Re-type new password:
Adding password for user user1

If htpasswd command is not recognized, make sure you have httpd installed:

yum install httpd

Make sure squid can read /etc/squid/passwd:

chmod o+r /etc/squid/passwd

Locate nsca_auth authentication helper

rpm -ql squid | grep ncsa_auth

Open /etc/squid/squid.conf file.
Add or edit the strings:

auth_param basic program /usr/lib/squid/ncsa_auth /etc/squid/passwd
auth_param basic children 5
auth_param basic realm Squid proxy-caching web server
auth_param basic credentialsttl 2 hours
auth_param basic casesensitive off

Add or edit these strings to acl section:

acl ncsa_users proxy_auth REQUIRED
http_access allow ncsa_users

Remember that position of strings in file is critical.
Here is a tested config file:

#
# 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


auth_param basic program /usr/lib64/squid/ncsa_auth /etc/squid/passwd
auth_param basic children 5
auth_param basic realm Squid proxy-caching web server
auth_param basic credentialsttl 2 hours
auth_param basic casesensitive off

# 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 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 Safe_ports port 8899
acl ncsa_users proxy_auth REQUIRED
acl CONNECT method CONNECT


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

# 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
http_access allow ncsa_users

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

# Squid normally listens to port 3128
http_port 8899

# 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

httpd_suppress_version_string on
forwarded_for off
visible_hostname squid.101

NOTE: the port is changed to 8899 from standard 3128

You can disable IPv6 by adding line

tcp_outgoing_address 0.0.0.0 all

Restart squid

/etc/init.d/squid restart

For allow squid start automatically during system startup :

chkconfig squid on

Also remember to check iptables if you cant connect/telnet squid port. For troubleshooting try to temporary disable iptables.

Here is example iptables rules:

iptables -A INPUT -p tcp -s 0/0 --sport 1024:65535 -d <serverIP> --dport <squidport> -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -s <serverip> --sport <squidport> -d 0/0 --dport 1024:65535 -m state --state ESTABLISHED -j ACCEPT

NOTE: since Squid 3.1.0 you may receive an error TCP_MISS/503 in /var/log/squid/access.log. If so, add the string tcp_outgoing_address <your public IP or domain name> in /etc/squid/squid.conf

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