[Firehol-support] Several dnat VNC services

Richard Williams richard at everything4it.co.uk
Thu Jun 14 10:34:36 BST 2007


Hi

 

I’m sorry if this has been raised before.

 

I’m trying to set up Firehol to route (dnat) external VNC services to
different computers, depending upon the TCP ports being used.  I’ve done
this successfully for two inputs on ports 5900 (default) and 7677 but when I
add a third on port 7674 if doesn’t get routed (it’s the one called vnc2
that’s to be routed to 10.0.0.4).  Unfortunately there’s nothing in the log
to show what’s going wrong.  I know that the receiving computer is able to
accept the VNC service on 7674 as there’s another gateway on the network and
I can route the traffic through that one successfully to 10.0.0.4.  However,
I’d prefer to use the Firehol protected gateway for operational reasons.

 

Here’s my firehol.conf that is based on one of the examples:

 

#

FIREHOL_LOG_LEVEL=error

# $Id: lan-gateway.conf,v 1.1 2003/10/12 13:43:42 ktsaou Exp $

#

# Configuration file for a LAN router with one ethernet interface (eth0)

# for the LAN and a PPP interface for connecting to the Internet.

#

# The LAN works with private IP addresses.

#

# This script will also setup a transparent cache for all the PCs on the

# local LAN.

 

#
----------------------------------------------------------------------------

# CUSTOM SERVICES

#
----------------------------------------------------------------------------

# See the section "Adding Services" in the documentation

 

# Example service x, listening on port TCP/z

# > server_x_ports="tcp/z"

# > client_x_ports="default"

server_vnc1_ports="tcp/7677"

client_vnc1_ports="default"

server_vnc2_ports="tcp/7674"

client_vnc2_ports="default"

#

#
----------------------------------------------------------------------------

# STOP UDP 2222 MESSAGES FLOODING SYSLOG

#
----------------------------------------------------------------------------
-

#

server_office_ports="udp/138"

client_office_ports="any"

#
----------------------------------------------------------------------------

# NETWORK DEFINITIONS - Normally, only these are to be touched by you.

#
----------------------------------------------------------------------------

# You can define anything you like, assuming you are using it later.

 

# --- HOME ---

 

# The definition of our HOME LAN.

HOME_MYIP="10.0.0.248"                     # The IP on our HOME LAN

HOME_MYIF="eth0"                  # The HOME LAN interface

HOME_BCAST="10.255.255.255"           # The HOME LAN broadcast

HOME_LAN="10.0.0.0/8"                       # The HOME LAN

HOME_SERVICES="all"

 

# Do we run a DHCP server on the HOME LAN?

HOME_DHCP=1                                    # Set to 0 to disable

 

 

# --- PUBLIC ---

 

# The definition of our PUBLIC interface.

PUBLIC_MYIP=""          # Leave empty for dynamic IP

PUBLIC_MYIF="ppp0"                # The public interface

PUBLIC_SERVICES="http ftp mysql"

 

# Is the PPP interface a DIAL-ON-DEMAND?

DIAL_ON_DEMAND=0               # Set to 0 to disable

 

 

# --- TRUSTED ---

 

# Hosts in the internet I trust for accessing private services

# Empty these to disable.

TRUSTED_IPS=""

TRUSTED_SERVICES=""

 

 

# --- TRANSPARENT CACHE ---

 

# Run a transparent cache?

SQUID_PORT="800"                  # Leave empty to disable SQUID

SQUID_USERS=""                     # Users to be excluded from the cache

SQUID_EXCLUDE=""                 # Web Server IPs to be excluded from the
cache

 

 

# --- BLACKLIST ---

 

# A space-separated list of IPs to be blocked.

blacklist=""

 

 

#
----------------------------------------------------------------------------

# HELPERS

#
----------------------------------------------------------------------------

 

# Block all traffic from/to certain IPs

if [ ! -z "${blacklist}" ]

then

            blacklist full "${blacklist}"

fi

 

# Setup a transparent squid, only if SQUID_PORT is set.

if [ ! -z "${SQUID_PORT}" ]

then

            transparent_squid "${SQUID_PORT}" "${SQUID_USERS}"            \

              inface "${HOME_MYIF}" src "${HOME_LAN}"                 \

              `test ! -z "${SQUID_EXCLUDE}" && echo "dst not
'${SQUID_EXCLUDE}'"`

fi

 

 

#
----------------------------------------------------------------------------

# NETWORK ADDRESS TRANSLATION

#
----------------------------------------------------------------------------

# Change the source/destination of packets...

 

# Should we do SNAT or MASQUERADE?

# If there is a PUBLIC_MYIP defined, we should do SNAT, otherwise MASQ.

#

if [ ! -z "${PUBLIC_MYIP}" ]

then

            snat to "${PUBLIC_MYIP}"
\

                        outface "${PUBLIC_MYIF}"
\

                        src "${HOME_LAN}" dst not "${UNROUTABLE_IPS}"

else

            masquerade "${PUBLIC_MYIF}"

fi

 

 

# To have some public service hit an internal machine, do this:

# (the example redirects external port TCP/26 to internal IP 10.0.0.2 port
25)

#

# > dnat to 10.0.0.2:25
\

# >       inface "${PUBLIC_MYIF}"
\

# >       src not "${HOME_LAN} ${UNROUTABLE_IPS}"
\

# >       proto tcp dport 26

#

# For each such statement, the router at the end has to support it.

dnat to 10.0.0.239:5900 inface ppp0 proto tcp dport 5900

dnat to 10.0.0.4:7674 inface ppp0 proto tcp dport 7674

dnat to 10.0.0.238:7677 inface ppp0 proto tcp dport 7677

#
----------------------------------------------------------------------------

# PROTECT SELF

#
----------------------------------------------------------------------------

# Protect the firewall host...

 

# --- HOME ---

 

# Protect us from the HOME LAN

interface "${HOME_MYIF}" home src "${HOME_LAN}" dst "${HOME_MYIP}
${HOME_BCAST}"

            policy reject

 

            server "${HOME_SERVICES}" accept

            client all accept

 

 

# DHCP needs 0.0.0.0/255.255.255.255 access.

if [ ${HOME_DHCP} -eq 1 ]

then

            interface "${HOME_MYIF}" dhcp

                        server dhcp accept

                        server office drop

fi

 

 

# --- PUBLIC ---

 

# Protect us from the PUBLIC

interface "${PUBLIC_MYIF}" internet
\

            src not "${UNROUTABLE_IPS}"
\

            `test ! -z "${PUBLIC_MYIP}" && echo "dst '${PUBLIC_MYIP}'"`

 

            protection strong

            policy drop

 

            # Are there any trusted PCs/services?

            if [ ! -z "${TRUSTED_PCS}" -a ! -z "${TRUSTED_SERVICES}" ]

            then

                        server "${TRUSTED_SERVICES}" accept src
"${TRUSTED_PCS}"

            fi

 

            server "${PUBLIC_SERVICES}" accept

 

            server custom rvw tcp/7676 default accept

            client all accept

 

# DIAL-ON-DEMAND needs this in case there is a PUBLIC_MYIP defined.

if [ ${DIAL_ON_DEMAND} -eq 1 ]

then

            interface "${PUBLIC_MYIF}" dialup

                        client all accept

fi

 

 

#
----------------------------------------------------------------------------

# PROTECT ROUTING

#
----------------------------------------------------------------------------

# Protect the LAN...

 

# Route traffic for the clients on the LAN

router internet2lan inface "${PUBLIC_MYIF}" outface "${HOME_MYIF}"      \

            src not "${UNROUTABLE_IPS}" dst "${HOME_LAN}"

 

            # route all client traffic

            client all accept

 

            server vnc accept dst 10.0.0.239

            server vnc1 accept dst 10.0.0.238

            server vnc2 accept dst 10.0.0.4

 

            # For the dnat example above, this is needed:

            # > server smtp accept dst 10.0.0.2

 

#
----------------------------------------------------------------------------

# SET LOG OPTIONS

#
----------------------------------------------------------------------------

FIREHOL_LOG_FREQUENCY="1/minute"

FIREHOL_LOG_BURST="5"

 

Regards

 

Richard Williams

 

****************************************************
Richard Williams
email: HYPERLINK
"mailto:richard at everything4it.co.uk"richard at everything4it.co.uk 
mobile: 07981 734697
**************************************************** 
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21:42
 
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