Difference between revisions of "Reverse Proxy with Squid"

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== Background ==
 
== Background ==
For my scenario I wished to run Apache and PHP. Indeed it is this combination on which this very site is running. In addition to this I
+
For my scenario I wished to run Apache and PHP. Indeed it is this combination on which this very site is running. For this HowTo I will be configuring squid on Ubuntu 7.10. The location of your configuration files may depend on your installation. However for this howto I will be assuming that your configuration files are under /etc/squid and the cache itself is under /var/squid.
Once Squid was compiled and installed I now had the following directory structure:
 
 
 
/usr/etc/squid.conf - Squid configuration file.<br>
 
/usr/var/logs - log file locations.<br>
 
/usr/var/cache - location of the cache itself.<br>
 
/usr/sbin/squid - location of the Squid executable.
 
  
 
== Editing squid.conf ==
 
== Editing squid.conf ==
Line 20: Line 14:
  
 
  http_port 80 accel defaultsite=www.sweetnam.eu vhost
 
  http_port 80 accel defaultsite=www.sweetnam.eu vhost
  forwarded_for on  
+
  forwarded_for on
  
 
The default site to be served is www.sweetnam.eu and we will use vhost directives to configure the other servers. In addition, the forwarded_for on is required for logging the original client address to the back end server. See below.
 
The default site to be served is www.sweetnam.eu and we will use vhost directives to configure the other servers. In addition, the forwarded_for on is required for logging the original client address to the back end server. See below.
Line 26: Line 20:
 
The next lines in the configuration are merely Squids default:
 
The next lines in the configuration are merely Squids default:
  
acl QUERY urlpath_regex cgi-bin \?
 
cache deny QUERY
 
acl apache rep_header Server ^Apache
 
broken_vary_encoding allow apache
 
 
 
access_log /usr/var/logs/access.log
 
cache_log /usr/var/logs/cache.log
 
cache_store_log /usr/var/logs/store.log
 
 
 
  refresh_pattern ^ftp:          1440    20%    10080
 
  refresh_pattern ^ftp:          1440    20%    10080
 
  refresh_pattern ^gopher:        1440    0%      1440
 
  refresh_pattern ^gopher:        1440    0%      1440
  refresh_pattern .              0      20%     
+
  refresh_pattern .              0      20%    4320
+
 
 
The next lines are where we begin to configure the two seperate servers.
 
The next lines are where we begin to configure the two seperate servers.
  
 
First we add a directive to tell Squid the IP address of the first server:
 
First we add a directive to tell Squid the IP address of the first server:
  
  cache_peer 172.20.1.10 parent 80 0 no-query originserver name=server_1
+
  cache_peer 172.20.1.10 parent 80 0 no-query originserver name=apache
 
   
 
   
You can see from above that we have given a name of server_1. All sites that will be hosted on this server will be under this group.
+
You can see from above that I have given a name of apache. All sites that will be hosted on this server will be under this group.
  
Next we must tell Squid the domains that will be served under server_1:
+
Next we must tell Squid the domains that will be served under apache:
  
  acl sites_server_1 dstdomain www.sample.com sample.com
+
  acl sites_apache dstdomain www.sample.com sample.com
 
  acl our_sites dstdomain www.sample.com sample.com
 
  acl our_sites dstdomain www.sample.com sample.com
  cache_peer_access server_1 allow sites_server_1
+
  cache_peer_access apache allow sites_apache
  
 
To add more domain names simply add them after the sample ones above.
 
To add more domain names simply add them after the sample ones above.
Line 58: Line 42:
 
Now we will configure the second server:
 
Now we will configure the second server:
  
  cache_peer 172.20.1.4 parent 80 0 no-query originserver name=server_2
+
  cache_peer 172.20.1.4 parent 80 0 no-query originserver name=iis
  acl sites_server_2 dstdomain www.sample2.com sample2.com
+
  acl sites_iis dstdomain www.sample2.com sample2.com
 
  acl our_sites2 dstdomain www.sample2.com sample2.com
 
  acl our_sites2 dstdomain www.sample2.com sample2.com
  cache_peer_access server_2 allow sites_server_2
+
  cache_peer_access iis allow sites_iis
 
 
And we now tell squid to allow access to the two servers:
 
 
 
http_access allow our_sites
 
http_access allow our_sites2
 
  
Next we must ensure that Squids acl rules are in place. For this I simply copied the defaults:
+
Next we must ensure that Squids default acl rules are in place. For this I simply copied the defaults:
  
 
  acl all src 0.0.0.0/0.0.0.0
 
  acl all src 0.0.0.0/0.0.0.0
Line 86: Line 65:
 
  acl Safe_ports port 777        # multiling http
 
  acl Safe_ports port 777        # multiling http
 
  acl CONNECT method CONNECT
 
  acl CONNECT method CONNECT
  http_access allow manager localhost
+
 
  http_access deny manager
+
Next we add two entries to allow the acls that we created for the backend servers:
 +
 
 +
http_access allow our_sites2
 +
http_access allow our_sites
 +
 
 +
And finally some more default configuration information:
 +
 
 +
  http_access allow manager all
 +
  http_access allow manager
 
  http_access deny !Safe_ports
 
  http_access deny !Safe_ports
 
  http_access deny CONNECT !SSL_ports
 
  http_access deny CONNECT !SSL_ports
 
  http_access deny all
 
  http_access deny all
icp_access allow all
 
 
   
 
   
 +
access_log /var/log/squid/access.log
 +
cache_mgr someone@somewhere.com
  
The last entries in our squid.conf are specific to your server:
 
  
cache_mgr admin@sample.com
+
And that's it your reverse proxy should now be configured and is ready to start serving requests. So you may now start squid but entering the following at a console:
cache_effective_user www-data
 
cache_effective_group www-data
 
visible_hostname hostname.sample.com
 
  
You may now start Squid with the following command:
+
/etc/init.d/squid start
 +
  
/usr/sbin/squid -sY -f /usr/etc/squid.conf
 
 
 
== Notes ==
 
== Notes ==
  
Line 112: Line 95:
  
 
== Complete squid.conf ==
 
== Complete squid.conf ==
 
Here is a complete squid.conf:
 
  
 
  http_port 80 accel defaultsite=www.sweetnam.eu vhost
 
  http_port 80 accel defaultsite=www.sweetnam.eu vhost
 
  forwarded_for on
 
  forwarded_for on
acl QUERY urlpath_regex cgi-bin \?
 
cache deny QUERY
 
acl apache rep_header Server ^Apache
 
broken_vary_encoding allow apache
 
 
 
access_log /usr/var/logs/access.log
 
cache_log /usr/var/logs/cache.log
 
cache_store_log /usr/var/logs/store.log
 
 
   
 
   
 
  refresh_pattern ^ftp:          1440    20%    10080
 
  refresh_pattern ^ftp:          1440    20%    10080
 
  refresh_pattern ^gopher:        1440    0%      1440
 
  refresh_pattern ^gopher:        1440    0%      1440
  refresh_pattern .              0      20%  
+
  refresh_pattern .              0      20%     4320
 
   
 
   
  acl sites_server_1 dstdomain www.sample.com sample.com
+
cache_peer 172.20.1.10 parent 80 0 no-query originserver name=apache
 +
  acl sites_apache dstdomain www.sample.com sample.com
 
  acl our_sites dstdomain www.sample.com sample.com
 
  acl our_sites dstdomain www.sample.com sample.com
  cache_peer_access server_1 allow sites_server_1
+
  cache_peer_access apache allow sites_apache
 
   
 
   
  cache_peer 172.20.1.4 parent 80 0 no-query originserver name=server_2
+
  cache_peer 172.20.1.4 parent 80 0 no-query originserver name=iis
  acl sites_server_2 dstdomain www.sample2.com sample2.com
+
  acl sites_iis dstdomain www.sample2.com sample2.com
 
  acl our_sites2 dstdomain www.sample2.com sample2.com
 
  acl our_sites2 dstdomain www.sample2.com sample2.com
  cache_peer_access server_2 allow sites_server_2
+
  cache_peer_access iis allow sites_iis
 
http_access allow our_sites
 
http_access allow our_sites2
 
 
   
 
   
 
  acl all src 0.0.0.0/0.0.0.0
 
  acl all src 0.0.0.0/0.0.0.0
Line 158: Line 129:
 
  acl Safe_ports port 777        # multiling http
 
  acl Safe_ports port 777        # multiling http
 
  acl CONNECT method CONNECT
 
  acl CONNECT method CONNECT
  http_access allow manager localhost
+
  http_access deny manager
+
http_access allow our_sites2
 +
http_access allow our_sites
 +
 +
  http_access allow manager all
 +
  http_access allow manager
 
  http_access deny !Safe_ports
 
  http_access deny !Safe_ports
 
  http_access deny CONNECT !SSL_ports
 
  http_access deny CONNECT !SSL_ports
 
  http_access deny all
 
  http_access deny all
icp_access allow all
 
 
cache_mgr admin@sample.com
 
cache_effective_user www-data
 
cache_effective_group www-data
 
visible_hostname hostname.sample.com
 
 
   
 
   
 +
access_log /var/log/squid/access.log
 +
cache_mgr someone@somewhere.com
 +
 +
 
 
== Configuring Logging to the back end servers ==
 
== Configuring Logging to the back end servers ==
  

Revision as of 20:15, 28 March 2008

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Introduction

If like me your ISP provides you with a single static IP address you may think that you are limited to running one web server. Or at the very best using NAT to ports other than port 80 on other servers. There are many reasons why you would wish to use more than one webserver. For example you may wish to have Apache serving one site and Microsoft IIS 6.0 serving another or even JBoss, Tomcat or some other application server.

Background

For my scenario I wished to run Apache and PHP. Indeed it is this combination on which this very site is running. For this HowTo I will be configuring squid on Ubuntu 7.10. The location of your configuration files may depend on your installation. However for this howto I will be assuming that your configuration files are under /etc/squid and the cache itself is under /var/squid.

Editing squid.conf

The supplied squid.conf is over 4000 lines long. Most of this is documentation added in the comments. For my purposes I created a new squid.conf from scratch.

By default Squid is configured to listen on TCP port 3128. As we wish to use Squid as a web server we need to tell it to listen on port 80 instead. So the first line of our new squid.conf is as follows:

http_port 80 accel defaultsite=www.sweetnam.eu vhost
forwarded_for on

The default site to be served is www.sweetnam.eu and we will use vhost directives to configure the other servers. In addition, the forwarded_for on is required for logging the original client address to the back end server. See below.

The next lines in the configuration are merely Squids default:

refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern .               0       20%     4320

The next lines are where we begin to configure the two seperate servers.

First we add a directive to tell Squid the IP address of the first server:

cache_peer 172.20.1.10 parent 80 0 no-query originserver name=apache

You can see from above that I have given a name of apache. All sites that will be hosted on this server will be under this group.

Next we must tell Squid the domains that will be served under apache:

acl sites_apache dstdomain www.sample.com sample.com
acl our_sites dstdomain www.sample.com sample.com
cache_peer_access apache allow sites_apache

To add more domain names simply add them after the sample ones above.

Now we will configure the second server:

cache_peer 172.20.1.4 parent 80 0 no-query originserver name=iis
acl sites_iis dstdomain www.sample2.com sample2.com
acl our_sites2 dstdomain www.sample2.com sample2.com
cache_peer_access iis allow sites_iis

Next we must ensure that Squids default acl rules are in place. For this I simply copied the defaults:

acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8
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

Next we add two entries to allow the acls that we created for the backend servers:

http_access allow our_sites2
http_access allow our_sites

And finally some more default configuration information:

http_access allow manager all
http_access allow manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access deny all

access_log /var/log/squid/access.log
cache_mgr someone@somewhere.com


And that's it your reverse proxy should now be configured and is ready to start serving requests. So you may now start squid but entering the following at a console:

/etc/init.d/squid start

Notes

All the above assumes that you have DNS configured so that each domain name that you have is pointing to the IP address of the reverse proxy.

The reverse proxy must be facing the internet. Either directly or by port forwarding.

Complete squid.conf

http_port 80 accel defaultsite=www.sweetnam.eu vhost
forwarded_for on

refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern .               0       20%     4320

cache_peer 172.20.1.10 parent 80 0 no-query originserver name=apache
acl sites_apache dstdomain www.sample.com sample.com
acl our_sites dstdomain www.sample.com sample.com
cache_peer_access apache allow sites_apache

cache_peer 172.20.1.4 parent 80 0 no-query originserver name=iis
acl sites_iis dstdomain www.sample2.com sample2.com
acl our_sites2 dstdomain www.sample2.com sample2.com
cache_peer_access iis allow sites_iis

acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8
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

http_access allow our_sites2
http_access allow our_sites

http_access allow manager all
http_access allow manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access deny all

access_log /var/log/squid/access.log
cache_mgr someone@somewhere.com


Configuring Logging to the back end servers

When using a reverse proxy you may notice that the logs on the back end servers will show hits as coming from the proxy rather then the client. There is a feature in Squid as noted earlier called forwarded_for on. This will pass the original clients IP address to the back end server. However you need to configure a custom log format on the back end server for logging to occur.

For Apache, I edited the httpd.conf and added a new line in the logging section called cached. This line as it appears in my configuration file looks like this:

LogFormat "%{X-Forwarded-For}i %v %u %t \"%r\" %>s %b \"%{Referer}i\"\"%{User-Agent}i\" cached

Now you need to configure your default sites or virtual hosts so that they will use the new log format. Simply locate the entry for your host and change the CustomLog entry so that it looks like this:

CustomLog /home/blog/logs/access_log cached

Once you have configured Apache you need to restart the service.

Thanks and Credits

Many thanks are owed to Paolo Marchiori and John Moylan of the Irish Linux Users Group who helped me figure out how to pass configure the custom log format for Apache.

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