1.1 Variables in squid.txt:

SQUID_MANAGER

Specifies the E-Mail-address of the local proxy administrator. This address is also the contact address in error message outputs. Likewise the E-Mail-address is used as the login for the cache manager. Default Setting is:

	SQUID_MANAGER='squid@fli4l'

SQUID_PASSWORD

Password for the cache manager.

Default Setting is:

	SQUID_PASSWORD='fli4l'

SQUID_TRANSPARENT_CACHING
SQUID_TRANSPARENT_FORWARDING

If activating this function, Squid filters all “surf accesses” from the internal net to the Internet and thus caches them. This can be of use if you want to cache those clients not explicitely having a proxy configured in their bowsers. The client does not recognize the redirection. The advantage:

  1. You can cache the line to the Internet even if you do not want to take care of the proper configuration of the clients.
  2. Programs not supporting a proxy will be cached as well and can make use of the “faster connection”
Default Setting is:
	SQUID_TRANSPARENT_CACHING='no'
	SQUID_TRANSPARENT_FORWARDING='no'


Important: If these options are set to 'yes', you can no longer use port forwarding on port 80. That would lead to a conflict and Squid would stop working.

Furthermore, access blocking for individual IP's in the base.txt is not working anymore! The fli4l itself always has full access to the Internet.

If transparent caching is enabled, an additional port will be opened to allow Squid to deliver certain pages (i.e. error pages) seamlessly. This is the value of SQUID_HTTP_Port (see below) plus one. So if SQUID_HTTP_Port=3128 is set, the port 3129 is also opened and hence may not be assigned to other applications on the flil4l.

SQUID_HTTP_PORT

Here you can specify on which TCP port Squid should wait for connections. Default Setting is:

	SQUID_HTTP_PORT='3128'


If transparent caching is enabled (SQUID_TRANSPARENT_CACHING='yes', see above), an additional port will be openend, SQUID_HTTP_PORT plus one. This port may not be assigned to other applications on the flil4l.

SQUID_MEM_CACHE_SIZE

This setting determines how much space the cache may take in RAM in maximum. Set the size in MB.

Recommended is 1/4 of the available main memory of the router.

SQUID_DISK_CACHE_SIZE

This setting determines how much space the cache is allowed to take on the hard disk as a maximum. Set the size in MB. While the cache gets bigger, Squid automatically deletes old files so that the maximum size is not exceeded. On the disk at least 25% should be still free at full cache because Squid becomes very slow when the disk is nearly full. If Squid has no space on the disk left to write files, it exits with an error.

Also note that Squid needs about 6 MB of RAM for itself plus the RAM specified at SQUID_MEM_CACHE_SIZE plus about 6 MB of RAM per GB of cache on the disk. The Squid process may not be swapped, physical memory must be available in corresponding amount!

When hitting problems set SQUID_DISK_CACHE_SIZE smaller. Squid with small cache is faster than Squid with big cache and not enough RAM.

SQUID_MAX_OBJECT_SIZE

The value is specified in kB. Objects that are larger than this value are not saved to disk. If you want to save a lot of traffic at the expense of high speed, you should set this value high. If you want higher speed at the expense of more traffic this value should be set to 10000 kB or less.

Default Setting is:

	SQUID_MAX_CACHE_SIZE='65536'

SQUID_WORK_DIR

In this directory Squid stores its cache, the log files, and other files relevant for operating.

The cache is stored in: SQUID_WORK_DIR/cache

Similarly, the logs: SQUID_WORK_DIR/logs

SQUID_WORK_DIR should therefore point to a hard disk with enough capacity. Important requirement is having read/write access and that the hard drive is formatted with the ext file system. More detailed information on disk preparation and use under fli4l can be found in the HD package.

Default Setting is:

	SQUID_WORK_DIR='/data/squid'

Alternatively, you may use 'auto' here so that the system path for persistent files is used. Pay attention to FLI4L_UUID pointing to a medium with sufficient space, otherwise /boot or if this is not writable even the RAMdisk will be used.

SQUID_CYCLE_LOG_N

This option determines the number of logfile rotations. If setting this to the value "0", the logfiles will only be closed and reopened. This allows you to rename the log files yourself.

Default Setting is:

	SQUID_CYCLE_LOG_N='10'

This equals 10 rotating log files.

SQUID_CYCLE_LOG_TIME

Since Squid, once it runs, mostly is performing without problems, it comes in handy that the log files regularly may be deleted automatically. This avoids that the hard drive will overflow. The value is specified in seconds. 1 hour corresponds to 3600 seconds.

Default Setting is:

	SQUID_CYCLE_LOG_TIME='172800'

This equals 48 hours.