From: Gary E. Miller (gem@rellim.com)
Date: Thu Sep 02 2004 - 12:34:25 EDT
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Yo Vinay!
No reason the proxy has to be INSIDE your firewall. All a user needs is
SSH, OpenVPN, or similar. Then they can set up an encrypted tunnel
from the local workstation to an external proxy or tunnel gateway.
If the guy setting it up is smart you will have to dig him out the hard
way. Set up tcpdump or ethereal on your internet gateway. Do
a capture of ALL the traffic, then go throught it all, eliminate the
"good" traffic and what is left is the "problem" traffic.
If they are good they can tunnel using DNS/udp or even an IP that is not
TCP, UDP or ICMP. If they are truly devious they could use Wi-Fi or
Cell Phones to just bypass your firewall completely.
The best way to catch them is to carry a 2x4 and do some MBWA (Management
By Walking Around). Fire the first guy you catch and the problem will
greatly diminish.
RGDS
GARY
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Gary E. Miller Rellim 20340 Empire Blvd, Suite E-3, Bend, OR 97701
gem@rellim.com Tel:+1(541)382-8588 Fax: +1(541)382-8676
On Thu, 2 Sep 2004, vinay mangal wrote:
> This problem is strictly with in company internet access firewall and in the
> LAN only. In a company, policy for Internet access says it is through IP
> only. The others can not browse the internet. This policy is implemented on
> firewall. Few smart guys have installed free proxy server running on non
> default ports and distributed the internet access to their friends. The
> firewall sees the traffic coming from the authorized IP and does not stop
> them. We want to know who has installed proxy on there machine.
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