[ILUG-Cochin.org] iptable,squid an dansguardien
sgeorge.ml at gmail.com
Fri Jul 15 15:15:47 IST 2011
On Fri, Jul 15, 2011 at 1:23 PM, prasanth kp <prasanthntr86 at gmail.com> wrote:
> i am a begginer in linux,so i have so many doubts in linux.so i will share
> my doubts with u
> 1.what is squid?(and its use)
Squid is a Proxy Server to start with for a beginner a beginner.
So Squid will sit most probably on your firewall.
When users in the LAN access http, https, ftp and such protocols the
proxy intersects it and the proxy connects to the servers on the
internet and fetched the data for them
Squid can also cache the files so when the next user asks for the same
file it can server the user from the cache and not fetch it again from
Squid can also act as a reverse proxy. A reverse web proxy sits in
front of web servers and caches the contents of the web server and
gives it to users accessing the web server.
Squid is actually called Squid-Cache
Apache can also act as a reverse proxy
Also there are other proxy/caches too like
to mention a few.
> 2.what is ip table?(and its use)
IP tables is the firewall that comes with the Linux kernel.
Most other firewalls in Linux are a front end to iptables.
Firewalls are some times called packet filters too. A few examples are.
The popular easy to configure Firewall suite pfSense is based on OpenBSD's PF.
> 3.what is dansguardien?(and its use)
Dansguardian is a content filter.
Let us say you use PF/NPF/IPF/IPTables as a firewall you can only
filter using IPs, Port Nos, protocols etc.
If you wanted to filter using URLs like you want to block all URLs
ending with .exe or .mp3 you should you some thing like Squid which
filters stuffs on a higer level.
But if you want to block web pages with some particular content the
you should use a content filter like dansguardian which filters on an
even more higher level.
Now if you want to know what the different levels are then read
> 4.What is transparent proxy?(and its use)
Well when you configure a proxy like squid you should make the users
enter the proxy information in their browser either manually or
In a transparent proxy the client side needs no configuration. the
proxy transparently does its job.
> i have a linux firewall in my office(Zentyal).Here i am using transparent
> proxy.i don't know what is this.My problem is ...i can block all http
> sites,but can't block https site.This is the major issues existing in my
> company.so pls help me
never used zentyal, but it you can do it with http then you should be
able to do it with https and ftp at least in any decent firewall :-)
hope this helps
More information about the Mailinglist