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Disclaimer: This manual is NOT a Squid tutorial. It is only a reference material that provides detailed explanation of all configuration parameters available in Squid 2.6. The reader is expected to have prior knowledge of basic Squid installation and configuration. For Complete tutorial on Squid, please visit http://www.squid-cache.org

Squid 2.6 Configuration Manual LOG FILE PATH NAMES AND CACHE DIRECTORIES   Squid provides a number of logs that can be used when debugging problems, and when measuring the effectiveness and identifying users and the sites they visit. Because Squid can be used to "snoop" on users browsing habits, one should carefully consider privacy laws in your region and more importantly be considerate to your users. That's being said, logs can be very valuable tools in insuring that your users get the best service possible from your cache. cache_dir logformat access_log cache_log cache_store_log cache_swap_log emulate_httpd_log log_ip_on_direct mime_table log_mime_hdrs useragent_log referer_log pid_filename debug_options log_fqdn client_netmask

TAG NAME                   cache_dir Description  This is used to define cache directory, its path, type and size Build Option  Default Usage  cache_dir Type Directory-Name FS-specfic-data [options]  Default  cache_dir ufs /usr/local/Squid/var/cache 100 16 256 Synopsis All objects which are to be cached are stored in the disk space defined by this tag. This defines the path to cache directory, cache directory name, type and size of the cache area. Arguments Type  Type specifies the kind of storage system to use. Only "ufs" is built by default. To enable any of the other storage systems see the  --enable-storeio configure option.  Type is one of the following:  1. ufs is the old well-known Squid storage format that has always been there.  2. aufs uses the same storage format as ufs, utilizing POSIX-threads to avoid blocking the main Squid process on disk-I/O.This was       formerly known in Squid as async-io.  3. diskd uses the same storage format as ufs, utilizing a separate process to avoid blocking the main Squid process on disk-I/O. Type  Usage ufs  cache_dir ufs Directory-Name Mbytes L1 L2 [options] aufs  cache_dir aufs Directory-Name Mbytes L1 L2 [options]s diskd  cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n] COSS   Directory-Name  Directory name is a top-level directory where cache swap files will be stored.If you want to use an entire disk for caching, then this can  be the mount-point directory. The directory must exist and be writable by the Squid process. Squid will NOT create this directory for  you. Mbytes  Mbytes is the amount of disk space (in MB) to use under this directory. The default is 100 MB. Change this to suit your configuration Level1  Number of first-level subdirectories which will be created under the Directory. The default is 16. Level2  number of second-level subdirectories which will be created under each first-level directory. The default is 256. Q1  number of unacknowledged I/O requests when Squid stops opening new files. If this many messages are in the queues, Squid won't  open new files. Default is 64. Q2  number of unacknowledged messages when Squid starts blocking. If this many messages are in the queues, Squid blocks until it  receives some replies. Default is 72. Option: read-only     Make the cache directory as read only. max-size=n   refers to the max object size this storedir supports. It is used to initially choose the storedir to dump the object. Note:    1. To make optimal use of the max-size limits you should order the cache_dir lines with the smallest max-size value first and the ones with no max-size specification last.    2. For coss, max-size must be less than COSS_MEMBUF_SZ Example(s) cache_dir ufs /path/to/cache_dir 5000 16 256       TAG NAME                   logformat Description  Defines the format for storing access logs in access.log file Build Option  Default Usage  logformat  <name> <format specification>  Default  none Synopsis Using this, the default log format can be changed according to the requirement. This customizable format will be needed when you want to perform analysis on the logs stored in access.log file. Arguments name  Identifier holding the customized logformat format specification  It is a string embedded with % format codes % format codes all follow the same basic structure where all but the formatcode is optional. Output strings are automatically quoted as required according to their context and the output format modifiers are usually unneeded but can be specified if an explicit quoting format is desired. The logformat name should be added at the end of access log file in the access_log tag. % ["|[|'|#] [-] [[0]width] [{argument}] formatcode "  quoted string output format [  Squid log quoted format as used by log_mime_hdrs #  URL quoted output format '  No automatic quoting -  left aligned width  field width. If starting with 0 then output is zero padded {arg}  argument such as header name etc Format codes:    >a   Client source IP address >A  Client FQDN >p  Client source port <A  Server IP address or peer name la  Local IP address (http_port) lp  Local port number (http_port) ts  Seconds since epoch tu  subsecond time (milliseconds) tl  Local time. Optional strftime format argument default %d/%b/%Y:%H:%M:S %z tg  GMT time. Optional strftime format argument default %d/%b/%Y:%H:%M:S %z tr  Response time (milliseconds) >h  Request header. Optional header name argument on the format header[:[separator]element] <h  Reply header. Optional header name argument as for >h un  User name ul  User login us  User SSL ui  User ident ue  User from external acl Hs  HTTP status code Ss  Squid request status (TCP_MISS etc) Sh  Squid hierarchy status (DEFAULT_PARENT etc) mt  MIME content type rm  Request method (GET/POST etc) ru  Request URL rv  Request protocol version ea  Log string returned by external acl <st   Reply size including HTTP headers >st  Request size including HTTP headers st  Request+Reply size including HTTP headers %  a literal % character Example(s) logformat Squid  %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh       TAG NAME                   access_log [previously called as cache_access_log] Description  Defines the file where client activities are logged Build Option  Default Usage  access_log <filepath> [<logformat name> [acl acl ...]] Default  access_log /usr/local/Squid/var/logs/access.log squid Synopsis All the activities the client does gets logged in this file. Using this, analysis on the access made by the clients can be done. Customization of the logging can be done using the acl's which logs only those clauses in the specified logformat. If no acl is specified, all requests will be logged to this file. To disable logging of a request specify "none". Arguments filepath  Location of the file that stores the logs logformat name  Identifier that holds the customized log formats acl  Filter rules to match Example(s) access_log /var/logs/access.log If logformat is configured, then define the access_log as shown to get the defined logformats. access_log /var/logs/access.log common, where common is the logformat name defined above.       TAG NAME                   cache_log Description  This tag is used to define the Cache logging file Build Option  Default Usage  cache_log <filepath>/filename  Default  cache_store_log /usr/local/Squid/var/logs/cache.log Synopsis This defines the path and the file where general information about your cache's behavior goes. This file contains startup configuration information, as well as assorted error information during Squid's operation. This file is a good place to look when a website is found to have problems running through the web cache. Entries here may point towards a potential solution. Arguments filepath  Specifies the location of the file filename  Actual file where the log is gathered   Example(s) cache_log /var/logs/cache.log       TAG NAME                   cache_store_log Description  Configures the location of the caches store log file Build Option  Default Usage  cache_store_log <filepath>/filename  Default  cache_store_log /usr/local/Squid/var/logs/store.log Synopsis This tag defines the location where the transaction log of all objects that are stored in the object store, as well as the time when the object get deleted. This file really doesn't have very much use on a production cache, and it primarily recommended for use in debugging. Therefore, it can be turned off by entering none in the entry field. Arguments filepath  Specifies the location of the file filename  Actual file where the log is gathered Example(s) cache_store_log /var/cache/store.log       TAG NAME                   cache_swap_log Description  Defines the filename used in each store directory to store the web caches metadata Build Option  Default Usage  cache_log <filepath>/filename  Default  none  Synopsis This tag defines the file where metadata of objects saved on disk. This is a form of index for the web cache object store. These metadata is used to rebuild the cache during startup. This is not a human readable log, and it is strongly recommended to leave it in its default location on each store directory. If %s can be used in the file name it will be replaced with a a representation of the cache_dir name where each / is replaced with ".". If have more than one 'cache_dir', and %s is not used in the name these swap logs will have names such as: 1. cache_swap_log.00 2. cache_swap_log.01 3. cache_swap_log.02 Note: You must give a full filename, not just a directory. Since this is the index for the whole object list you CANNOT periodically rotate it! Arguments filepath  Specifies the location of the file filename  Actual file where the log is gathered Example(s) cache_swap_log /var/cache/cache_swap.log       TAG NAME                   emulate_httpd_log escription  Allows you to specify that Squid write its access.log in HTTPD common log file format Build Option  Default Usage  emulate_httpd_log on|off      Default  emulate_httpd_log off  Synopsis Squid write its access.log in HTTPD common log file format, such as that used by Apache and many other web servers. This allows you to parse the log and generate reports using a wider array of tools. However, this format does not provide several types of information specific to caches, and is generally less useful when tracking cache usage and solving problems. Because there are several effective tools for parsing and generating reports from the Squid standard access logs, it is usually preferable to leave this at its default of being off. Arguments on/off  Enable or disable this process       TAG NAME                   log_ip_on_direct Description  This tag enables/disables logging of IP adress/hostname in the access.log file Build Option  Default Usage  log_ip_on_direct on|off Default  log_ip_on_direct on  Synopsis By making this directive to on, logs the IP Address of the destination server in the access.log file. If you want the hostname to be logged, then configure the directive to off mode. Arguments on/off  Enable or disable this process       TAG NAME                   mime_table Description  Used to define the file and path to the file where Squid's mime table is located Build Option  Default Usage  mime_table path/filename Default  mime_table /usr/local/Squid/etc/mime.conf  Synopsis Squid uses the mime table defined by this tag Arguments path  Path for the file where mime table file is located filename  File that contains mime table Example(s) mime_table /usr/local//mime.conf       TAG NAME                   log_mime_hdrs Description  Enables to log extra information about clients requests in the access log Build Option  Default Usage  log_mime_hdrs on|off Default  log_mime_hdrs off  Synopsis When enabled, causes Squid to log more information about the request in the access.log file. This causes Squid to also write the request and response MIME headers for every request. These will appear in brackets at the end of each access.log entry. Arguments on/off  Enable or disable this process       TAG NAME                   useragent_log Description  Using this tag, you can make Squid to write User-Agent field from HTTP requests to the filename specified in this tag Build Option  --enable-useragent-log Usage  useragent_log path/filename Default  none  Synopsis By default useragent_log is disabled. Arguments path  Path for the useragent log file filename  File that contains useragent logs Example(s) useragent_log /var/logs/usragent.log       TAG NAME                   referer_log Description  Squid will write the Referer field from HTTP requests to the filename specified here Build Option  --enable-referer-log Usage  referer_log path/filename Default  none  Synopsis By default referer_log is disabled. Arguments path  Path for the referer log file filename  File that contains useragent logs Example(s) referer_log /var/logs/referer.log       TAG NAME                   pid_filename Description  Used to define a filename where the process id's of Squid is stored Build Option  Default Usage  pid_filename path/filename Default  pid_filename /usr/local/Squid/var/logs/Squid.pid Synopsis If you don't want Squid to create this file enter none instead of filename. Arguments path  Path for the Squid pid file filename  File that contains pid of Squid's process Example(s) pid_filename /usr/local/Squid.pid       TAG NAME                   debug_options Description  This provides a means to configure all of Squid's various debug sections Build Option  Default Usage  debug_options section, level Default  debug_options ALL,1 Synopsis Squid's debugging code has been divided into a number of sections, so that if there is a problem in one part of Squid debug logging can be made more verbose for just that section. The magic word "ALL" sets debugging levels for all sections.  We recommend normally running with "ALL,1". Arguments section  Defines which section's information to be logged level  Defines debugging levels (0-9) Example(s) debug_options ALL, 9       TAG NAME                   log_fqdn Description  Turn this on if you wish to log fully qualified domain names in the access.log Build Option  Default Usage  log_fqdn on|off Default  log_fqdn off Synopsis This configures whether Squid will attempt to resolve the hostname, so the the fully qualified domain name can be logged. This can, in some cases, increase latency of requests. Arguments on/off  Enable or disable this process       TAG NAME                   client_netmask Description  Defines what portion of the requesting client IP is logged in the access.log Build Option  Default Usage  client_netmask netmask Default  client_netmask 255.255.255.255 Synopsis You can make the requesting clients IP to be logged as such or only the network part of the IP alone with the host part being zero. For privacy reasons it is often preferred to only log the network or subnet IP of the client. For example, a netmask of 255.255.255.0 will log the first three octets of the IP, and fill the last octet with a zero. Arguments netmask  Clients network mask Example(s) client_netmask 255.255.120.200