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The Graveyard - Products No Longer Supported => D-Link NetDefend Firewalls => Topic started by: lezde716 on July 20, 2010, 05:10:03 PM

Title: how to block proxy site
Post by: lezde716 on July 20, 2010, 05:10:03 PM
My dfl-800 is configured to block facebook and frienster but when you use a proxy site you can still open the facebook or a web site that is being blocked. the idea is you block again this proxy site.

any idea how to work this out aside from blocking the proxy site?  step by step guide is highly appreciated. thank you.
Title: Re: how to block proxy site
Post by: danilovav on July 20, 2010, 08:03:35 PM
There is two plicies avaliable

1) Block everything except allowed
It possible thru HTTP ALG, add blacklist * and whitelist records for allowed sites

2) Check what users use and block this sites one by one
Title: Re: how to block proxy site
Post by: chechito on July 20, 2010, 08:29:18 PM
some IDP rules apply for proxy detection, y personally use opendns proxy-anonymous category to filter dns requests.

Blocking ports frequently used by proxy may help a little (except 80 of course)
Title: Re: how to block proxy site
Post by: danilovav on July 21, 2010, 12:04:13 PM
OpenDNS - good idea to block public proxies. But private... useles...
Title: Re: how to block proxy site
Post by: lezde716 on July 21, 2010, 04:49:26 PM
Quote from: danilovav on July 21, 2010, 12:04:13 PM
OpenDNS - good idea to block public proxies. But private... useles...

How do I configure this OpenDNS I don't know where to start configuring this thing. can you please gave a little step on how to do this. thank you...
Title: Re: how to block proxy site
Post by: chechito on July 21, 2010, 05:21:53 PM
Quote from: danilovav on July 21, 2010, 12:04:13 PM
OpenDNS - good idea to block public proxies. But private... useles...

yeah totally true
Title: Re: how to block proxy site
Post by: danilovav on July 21, 2010, 08:11:11 PM
Quote from: lezde716 on July 21, 2010, 04:49:26 PM
How do I configure this OpenDNS I don't know where to start configuring this thing. can you please gave a little step on how to do this. thank you...
Just register on opendns.com and use provided servers instread of your ISP servers

Quote from: chechito on July 21, 2010, 05:21:53 PM
yeah totally true
If problem to block proxies is staying hard, you can follow some ways, but no one depends only from DFL
1) keep traffic stats and check what sites users visited and block new denied
2) configure squid as transparent proxy. As i heard, it's very flexible system and for example you can configure auto block of all new websites what reached limit
3) change your HR policy :)

In my experience, i used 1st way and it was enought. For testing, i wanna to try configure squid, but now unfortunately i have no required time...
Title: Re: how to block proxy site
Post by: lezde716 on July 21, 2010, 11:25:24 PM
thanks everybody for answering my concern, I will try to setup a squid for my transparent proxy.
Title: Re: how to block proxy site
Post by: danilovav on July 22, 2010, 04:53:35 PM
Let us know the result :)