This is a new option to replace a formerly hard-coded value. It specifies the size limit for objects kept in memory. Objects larger than this can not be kept in memory.

This is similar to the old replacement_policy. It specifies the cache replacement algorithm to be used for the disk cache.

This option specifies the replacement algorithm for the memory cache.

This new option, which defaults on ON, makes Squid log the origin server's IP address in the 9th field of the access.log file for DIRECT requests. If you turn this option OFF, Squid reverts to the former behavior and logs the hostname or whatever was given in the URL.

With this option you can create a logfile that contains HTTP referer headers.

This option makes a formerly hard-coded value configurable. It specifies the initial retransmit interval for internal DNS queries.

This option makes a formerly hard-coded value configurable. It specifies the amount of time to wait for an answer from an internal DNS query. After this amount of time Squid gives up and returns an error.

With this enabled Squid denies requests if a user appears to change IP addresses within the authenticate_ip_ttl time.

This new access control element type allows you to use the request content-type in access controls.

When this option is enabled, Squid forwards all httpd_accel requests to the httpd_accel_host, regardless of Host headers and redirector changes.

This option requires the --enable-icmp configure option. If the ICMP database reports that the round-trip time to the origin server is less than this limit, then the request is sent directly to the origin server, rather than a neighbor cache.

By default, Squid sends any non-hierarchical requests (matching hierarchy_stoplist or not cachable request type) directly to origin servers. If you turn nonhierarchical_direct off, Squid will prefer to send these requests to neighbors.

Squid only knows about standard HTTP request methods. Unknown methods are denied, unless you add them to this list.

If you set this option, Squid will print a warning to cache.log and syslog if the median response time goes above this limit.

If you set this option, Squid will print a warning to cache.log and syslog if the page fault rate goes above this limit.

If you set this option, Squid will print a warning to cache.log and syslog if the memory usage goes above this limit.

Squid currently supports two algorithms for selecting cache directories for new objects: least-load and round-robin. The default is least-load.

Enables a hack for Microsoft Internet Explorer versions that don't send 'no-cache' request headers when the user presses the reload button.

A new cache_dir storage type, called diskd has been added. Diskd uses external (child) processes to perform all cache disk I/O operations (open, close, read, write, unlink). I/O requests are sent to diskd processes over message queues. Shared memory is used for reading and writing data buffers. For more information, please see the Diskd FAQ section.

If you want to run Squid as a proxy, without caching anything, then the null storage type may be useful. Although it won't use any disk space, it still keeps some statistics that you might like to have.

Use this option to specify which storage modules to build. Possible values are: aufs, coss, diskd, null, ufs. The default is ufs, which is highly recommend for new users. The other modules may not work for all users.

Use this option if you want more removal policy choices than basic LRU.

Use this option to specify the COSS storage system buffer size.

Use this option if you're using transparent caching on a Linux 2.4.0 or higher kernel.

Use this option to select which proxy authentication backend modules to use. Possible choices are: LDAP, MSNT, NCSA, PAM, SMB, YP, getpwnam, multi-domain-NTLM.

Use this option to disable the external file deletion daemon process.

Your operating system may have support for automatically generating stack traces. Use this option to enable that feature, but don't expect it to work on your particular operating system.

To avoid naming collisions with other programs, Squid now puts certain ``helper'' programs into $prefix/squid/libexec. The unlinkd, pinger, and diskd programs will all go into this directory by default. If your squid.conf has pathnames for some of these programs, you will need to change it. Also don't forget to run make install-pinger as root to install it in the new location.