Update the transparent HTTP proxy example:

Include filters to block some well-known instant messengers; thanks to
Rene Badalassi (rene at cybersecure dot com dot au) for providing the
examples.
(This change depends on my latest fix to hoststated)

src/etc/hoststated.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: hoststated.conf,v 1.7 2007/10/22 08:44:54 reyk Exp $
+# $OpenBSD: hoststated.conf,v 1.8 2007/11/19 15:09:32 reyk Exp $
 #
 # Macros
 #
@@ -92,8 +92,16 @@ relay sshgw {
 #
 protocol httpfilter {
 	protocol http
+
+	# Block disallowed browsers
 	header filter "Mozilla/4.0 (compatible; MSIE *" from "User-Agent"
-	response header filter "application/*" from "Content-Type"
+
+	# Block some well-known Instant Messengers
+	response header filter "application/x-msn-messenger" from "Content-Type"
+	response header filter "app/x-hotbar-xip20" from "Content-Type"
+	response header filter "application/x-icq" from "Content-Type"
+	response header filter "AIM/HTTP" from "Content-Type"
+	response header filter "application/x-comet-log" from "Content-Type"
 }
 
 relay httpproxy {

src/etc/relayd.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: relayd.conf,v 1.7 2007/10/22 08:44:54 reyk Exp $
+# $OpenBSD: relayd.conf,v 1.8 2007/11/19 15:09:32 reyk Exp $
 #
 # Macros
 #
@@ -92,8 +92,16 @@ relay sshgw {
 #
 protocol httpfilter {
 	protocol http
+
+	# Block disallowed browsers
 	header filter "Mozilla/4.0 (compatible; MSIE *" from "User-Agent"
-	response header filter "application/*" from "Content-Type"
+
+	# Block some well-known Instant Messengers
+	response header filter "application/x-msn-messenger" from "Content-Type"
+	response header filter "app/x-hotbar-xip20" from "Content-Type"
+	response header filter "application/x-icq" from "Content-Type"
+	response header filter "AIM/HTTP" from "Content-Type"
+	response header filter "application/x-comet-log" from "Content-Type"
 }
 
 relay httpproxy {