Specifications

Squid will make a note of the failed requests then refuse to issue new
ones, although the Internet connection has been reestablished. In a case
such as this, change the minutes to seconds then, after clicking on
Reload in the browser, the dial-up process should be reengaged after a
few seconds.
never_direct allow <acl_name> To prevent Squid from taking requests di-
rectly from the Internet, use this command to force connection to an-
other proxy. You need to have previously entered this in cache_peer.
If all is specified as the <acl_name>, force all requests to be for-
warded directly to the parent. This might be necessary, for example, if
you are using a provider which strictly stipulates the use of its proxies
or denies its firewall direct Internet access.
Options for Access Controls
Squid provides an intelligent system that controls access to the proxy. By im-
plementing ACLs, it can be configured easily and comprehensively. This in-
volves lists with rules processed sequentially. ACLs must be defined before
they can be used. Some default ACLs, such as all and localhost, already
exist. After defining an ACL, implement it, for example, in conjunction with
http_access.
acl <acl_name> <type> <data> An ACL requires at least three specifica-
tions to define it. The name <acl_name> can be arbitrarily chosen.
For <type>, select from a variety of different options in the ACCESS
CONTROLS section in the /etc/squid.conf file. The specification
for <data> depends on the individual ACL type and can also be read
from a file, for example, via host names, IP addresses, or URLs. In the
following are some simple examples:
acl mysurfers srcdomain .my-domain.com acl teachers
src 192.168.1.0/255.255.255.0 acl students src
192.168.7.0-192.168.9.0/255.255.255.0 acl lunch time MTWHF
12:00-15:00
http_access allow <acl_name> http_access defines who is allowed to
use the proxy and also who can access what on the Internet. For this,
ACLs must be given. localhost and all have already been defined
above, which can deny or allow access via deny or allow. A list con-
taining any number of http_access entries can be created. They will
be processed from top to bottom and, depending on which occurs first,
access will be allowed or denied to the respective URL. The last entry
176 The Configuration File /etc/squid.conf