Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Message-ID: <42B41CCC.9D7D70A7@dessent.net>
Date: Sat, 18 Jun 2005 06:08:28 -0700
From: Brian Dessent <brian AT dessent DOT net>
MIME-Version: 1.0
To: cygwin AT cygwin DOT com
Subject: Re: Cygwin and firewalls
References: <d8v8ru$9mt$1 AT sea DOT gmane DOT org> <d90unl$rc2$1 AT sea DOT gmane DOT org>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Spam-Report: -5.8/5.0 ---- Start SpamAssassin results  	* -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 	* -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% 	*      [score: 0.0000] 	*  0.0 AWL AWL: From: address is in the auto white-list 	---- End SpamAssassin results
X-IsSubscribed: yes
Reply-To: cygwin AT cygwin DOT com

Andrew Schulman wrote:

> Why is this a Cygwin question?  A firewall is a firewall.  Network
> applications, both Cygwin and non-Cygwin, have to deal with it.  I don't
> know what a Cygwin-hostile firewall would look like.

Cygwin uses sockets to implement many of its functions, such as IPC. 
Some overzealous firewalls install themselves deeply into the winsock
stack (I believe it's called 'layered service provider' API) and install
hooks throughout.  This can cause things to break if the firewall
implementation is not done properly and without bugs, or causes the
semantics of socket operations to change.  See for example, the threads
about crappy VPN clients causing cygwin programs to hang, or the
Zonealarm firewall causing the X11 server to hang at startup.  Sadly the
archives are littered with examples of poorly written firewall-type
software that causes things to break, so it's not such a stupid
question.

Brian

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/