Copyright © 2006, 2007 Thomas M. Eastep
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover, and with no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”.
2023/02/18
Table of Contents
Caution
This article applies to Shorewall 4.0 and later. If you are running a version of Shorewall earlier than Shorewall 4.0.0 then please see the documentation for that release.
Prior to adopting Xen, I had a home office crowded with 5 systems, three monitors a scanner and a printer. The systems were:
Firewall
Public Server in a DMZ (mail)
Private Server (wookie)
My personal Linux Desktop (ursa)
My work system (docked laptop running Windows XP).
The result was a very crowded and noisy room.
Xen has allowed me to reduce the noise and clutter considerably. I now have three systems with two monitors. I've also replaced the individual printer and scanner with a Multifunction FAX/Scanner/Printer.
The systems now include:
Combination Firewall/Public Server/Private Server/Wireless Gateway using Xen (created by building out my Linux desktop system -- Now replaced by a Hewlett-Packard Pavilion a1510y).
My work system.
My Linux desktop (wookie, which is actually the old public server box)
The Linux systems run either OpenSuSE ™10.3 or Ubuntu™ "Gutsy Gibbon".
Here is a high-level diagram of our network.
As shown in this diagram, the Xen system has three physical network interfaces. These are:
eth0-- connected to our DSL "Modem".eth1-- connected to the switch in my office.eth2-- connected to a Wireless Access Point (WAP) that interfaces to our wireless network.
There are three Xen domains.
Dom0 (DNS name gateway.shorewall.net) is used as our main firewall and wireless gateway as well as a local file server. It hosts Squid running as a transparent HTTP proxy and a DHCP server that manages IP address assignment for both the LAN and the Wireless network.
A DomU (Domain name lists, DNS name lists.shorewall.net) that is used as a public Web/FTP/Mail/DNS server.
A DomU (Domain name test, DNS name test.shorewall.net) that I use for Shorewall testing.
Shorewall runs in Dom0.
Caution
As the developer of Shorewall, I have enough experience to be very comfortable with Linux networking and Shorewall/iptables. I arrived at this configuration after a fair amount of trial and error experimentation (see Xen and the art of Consolidation). If you are a Linux networking novice, I recommend that you do not attempt a configuration like this one for your first Shorewall installation. You are very likely to frustrate both yourself and the Shorewall support team. Rather I suggest that you start with something simple like a standalone installation in a DomU; once you are comfortable with that then you will be ready to try something more substantial.
As Paul Gear says: Shorewall might make iptables easy, but it doesn't make understanding fundamental networking principles, traffic shaping, or multi-ISP routing any easier.
The same goes for Xen networking.
Below are the relevant configuration files for the two domains. I use a partition on my hard drives for the DomU storage device.
There is not much documentation about how to configure Xen for routed operation. I've tried to mark the relevant parts with bold font.
Important
The files from /etc/xen/auto shown below correspond to
my configuration under Xen 3.0. I'm now running Xen 3.1 which does
not use configuration files for the domains but rather keeps the
configuration in a database managed by xend. See below.
/boot/grub/menu.lst— here is the entry that boots Xen in Dom0.title Kernel-2.6.18.8-0.1-xen root (hd0,5) kernel /boot/xen.gz module /boot/vmlinuz-2.6.18.8-0.1-xen root=/dev/sda6 vga=0x31a resume=/dev/sda5 splash=silent showopts module /boot/initrd-2.6.18.8-0.1-xen
/etc/modprobe.conf.local(This may need to go in/etc/modprobe.confor/etc/modprobe.d/optionson your system)options netloop nloopbacks=0 #Stop netloop from creating 8 useless vifs
/etc/xen/auto/01-lists— configuration file for the lists domain. Placed in/etc/xen/auto/so it is started automatically by Xen's xendomains service.disk = [ 'phy:/dev/sda9,hda,w', 'phy:/dev/hda,hdb,r' ] memory = 512 vcpus = 1 builder = 'linux' name = 'server' vif = [ 'mac=00:16:3e:b1:d7:90, ip=206.124.146.177, vifname=eth3' ] localtime = 0 on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' extra = ' TERM=xterm' bootloader = '/usr/lib/xen/boot/domUloader.py' bootentry = 'hda2:/boot/vmlinuz-xen,/boot/initrd-xen'Note that the vifname is set to 'eth3' for the virtual interface to this DomU. This will cause the Dom0 interface to the server to have a fixed name (
eth3) which makes it a lot easier to deal with in Shorewall and elsewhere.Specifying an IP address (ip=206.124.146.177) causes the vif-route script to create a host route to that IP address on
eth3.gateway:~ # ip route ls dev eth3 206.124.146.177 scope link src 206.124.146.176 gateway:~ #Note that the source for the route is 206.124.146.176. That is the primary IP address of Dom0's
eth0. Xen configureseth3to have that same IP address.
/etc/xen/auto/02-test— configuration file for the test domain.disk = [ 'phy:/dev/hdb4,hda,w', 'phy:/dev/hda,hdb,r' ] memory = 512 vcpus = 1 builder = 'linux' name = 'test' vif = [ 'mac=00:16:3e:83:ad:28, ip=192.168.1.7, vifname=eth4' ] localtime = 0 on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' extra = ' TERM=xterm' bootloader = '/usr/lib/xen/boot/domUloader.py' bootentry = 'hda2:/boot/vmlinuz-xen,/boot/initrd-xen'Excerpt from
/etc/xen/xend-config.sxp:… # It is possible to use the network-bridge script in more complicated # scenarios, such as having two outgoing interfaces, with two bridges, and # two fake interfaces per guest domain. To do things like this, write # yourself a wrapper script, and call network-bridge from it, as appropriate. # #(network-script network-bridge) … # If you are using only one bridge, the vif-bridge script will discover that, # so there is no need to specify it explicitly. # #(vif-script vif-bridge) ## Use the following if network traffic is routed, as an alternative to the # settings for bridged networking given above. (network-script network-route) (vif-script vif-route)Important
As of this writing, the vif-route script does not set up Proxy ARP correctly. So the domU can communicate with the dom0 but not with hosts beyond the dom0.
If you configure Shorewall as described below, Shorewall will correct the Proxy ARP configuration so that it will work.
Instructions for editing entries in the Xen 3.1 xend database may be found at http://www.novell.com/documentation/vmserver/config_options/index.html?page=/documentation/vmserver/config_options/data/b8uh3zr.html, The following are excerpts from the XML representations of the two user domains (produced by "xm list -l …").
lists domain:
…
(features )
(on_xend_start start)
(on_xend_stop shutdown)
(start_time 1194710550.49)
…
(console_mfn 397179)
(device
(vif
(mac 00:16:3e:b1:d7:90)
(script vif-route)
(ip 206.124.146.177)
(vifname eth3)
(type netfront)
(devid 0)
(uuid 55676385-7b69-09fd-4027-751b692ead75)
)
)
(device
(vbd
…test domain:
…
(console_mfn 418003)
(device
(vif
(uuid 64a1dd48-fa8b-7561-e90b-cd589cbeb7fa)
(script vif-route)
(ip 192.168.1.7)
(mac 00:16:3e:83:ad:28)
(vifname eth4)
(devid 0)
(type netfront)
(backend 0)
)
)
(device
(vbd
…With the three Xen domains up and running, the system looks as shown in the following diagram.
The zones correspond to the Shorewall zones in the Dom0 configuration.
Readers who are paying attention will notice that eth4 has the same public IP address (206.124.146.176) as eth0 (and eth3), yet the test system connected to that interface has an RFC 1918 address (192.168.1.7). That configuration is established by Xen which clones the primary IP address of eth0 on all of the routed virtual interfaces that it creates. test is configured with its default route via 192.168.1.254 which is the IP address of the firewall's br0. That works because of the way that the Linux network stack treats local IPv4 addresses; by default, it will respond to ARP "who-has" broadcasts for any local address and not just for the addresses on the interface that received the broadcast (but of course the MAC address returned in the "here-is" response is that of the interface that received the broadcast). So when test broadcasts "who-has 192.168.1.254", the firewall responds with "here-is 192.168.1.254 00:16:3e:83:ad:28" (00:16:3e:83:ad:28 is the MAC of virtual interface eth4).
Caution
Under some circumstances, UDP and/or TCP communication from a
DomU won't work for no obvious reason. That happened with the
lists domain in my setup. Looking at
the IP traffic with tcpdump -nvvi eth1 in Dom0
showed that UDP packets from the lists DomU had incorrect checksums. That
problem was corrected by arranging for the following command to be
executed in the lists and test domains when the eth0 device was brought up:
ethtool -K eth0 tx off
Under OpenSuSE™ 10.2, I placed the
following in
/etc/sysconfig/network/ifcfg-eth-id-00:16:3e:b1:d7:90
ETHTOOL_OPTIONS='-K iface tx off'
Under other distributions, the technique will vary. For example,
under Debian™ or Ubuntu™,
you can just add a 'post-up' entry to
/etc/network/interfaces as shown here:
iface eth0 inet static
address 206.124.146.177
netmask 255.255.255.0
post-up ethtool -K eth0 tx offCaution
Update. Under OpenSuSE 10.2, communication from a domU works okay without running ethtool but traffic shaping in dom0 doesn't work! So it's a good idea to run it just to be safe.
In Dom0, I run a conventional three-interface firewall with Proxy ARP DMZ -- it is very similar to the firewall described in the Shorewall Setup Guide with the exception that I've added a fourth interface for our wireless network. The firewall runs a routed OpenVPN server to provide road warrior access for our three laptops and a bridged OpenVPN server for the wireless network in our home. Here is the firewall's view of the network:
The three laptops can be directly attached to the LAN as shown above or they can be attached wirelessly -- their IP addresses are the same in either case; when they are directly attached, the IP address is assigned by the DHCP server running in Dom0 and when they are attached wirelessly, the IP address is assigned by OpenVPN.
The Shorewall configuration files are shown below. All routing and secondary IP addresses are handled in the OpenSuSE network configuration.
/etc/shorewall/shorewall.conf
STARTUP_ENABLED=Yes VERBOSITY=0 SHOREWALL_COMPILER=perl LOGFILE=/var/log/firewall LOGFORMAT="Shorewall:%s:%s:" LOGTAGONLY=No LOGRATE= LOGBURST= LOGALLNEW= BLACKLIST_LOGLEVEL= MACLIST_LOG_LEVEL=$LOG TCP_FLAGS_LOG_LEVEL=$LOG SMURF_LOG_LEVEL=$LOG LOG_MARTIANS=No IPTABLES= SHOREWALL_SHELL=/bin/ash SUBSYSLOCK=/var/lock/subsys/shorewall MODULESDIR= CONFIG_PATH=/etc/shorewall:/usr/share/shorewall RESTOREFILE= IPSECFILE=zones LOCKFILE= DROP_DEFAULT="Drop" REJECT_DEFAULT="Reject" ACCEPT_DEFAULT="none" QUEUE_DEFAULT="none" IP_FORWARDING=Yes ADD_IP_ALIASES=No ADD_SNAT_ALIASES=No RETAIN_ALIASES=No TC_ENABLED=internal TC_EXPERT=No CLEAR_TC=Yes MARK_IN_FORWARD_CHAIN=Yes CLAMPMSS=Yes ROUTE_FILTER=No DETECT_DNAT_IPADDRS=Yes MUTEX_TIMEOUT=60 ADMINISABSENTMINDED=Yes BLACKLISTNEWONLY=Yes DELAYBLACKLISTLOAD=No MODULE_SUFFIX= DISABLE_IPV6=Yes BRIDGING=No DYNAMIC_ZONES=No PKTTYPE=No MACLIST_TABLE=mangle MACLIST_TTL=60 SAVE_IPSETS=No MAPOLDACTIONS=No FASTACCEPT=Yes IMPLICIT_CONTINUE=Yes HIGH_ROUTE_MARKS=Yes USE_ACTIONS=Yes OPTIMIZE=1 EXPORTPARAMS=No EXPAND_POLICIES=Yes KEEP_RT_TABLES=No DELETE_THEN_ADD=No BLACKLIST_DISPOSITION=DROP MACLIST_DISPOSITION=DROP TCP_FLAGS_DISPOSITION=DROP
/etc/shorewall/zones:#ZONE TYPE OPTIONS IN_OPTIONS OUT_OPTIONS fw firewall #The firewall itself. net ipv4 #Internet loc ipv4 #Local wired Zone dmz ipv4 #DMZ vpn ipv4 #Open VPN clients wifi ipv4 #Local Wireless Zone
/etc/shorewall/policy:#SOURCE DEST POLICY LOGLEVEL LIMIT $FW $FW ACCEPT $FW net ACCEPT loc net ACCEPT $FW vpn ACCEPT vpn net ACCEPT vpn loc ACCEPT loc vpn ACCEPT $FW loc ACCEPT loc $FW ACCEPT wifi all REJECT $LOG net $FW DROP $LOG 1/sec:2 net loc DROP $LOG 2/sec:4 net dmz DROP $LOG 8/sec:30 net vpn DROP $LOG all all REJECT $LOG
Note that the firewall<->local network interface is wide open so from a security point of view, the firewall system is part of the local zone.
/etc/shorewall/params (edited):MIRRORS=<comma-separated list of Shorewall mirrors> NTPSERVERS=<comma-separated list of NTP servers I sync with> POPSERVERS=<comma-separated list of server IP addresses> LOG=info INT_IF=br0 DMZ_IF=eth3 EXT_IF=eth0 WIFI_IF=eth2 TEST_IF=eth4 OMAK=<IP address at our second home>
/etc/shorewall/init:echo 1 > /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_be_liberal
/etc/shorewall/interfaces(don't specify the BROADCAST addresses if you are using Shorewall-perl):#ZONE INTERFACE BROADCAST OPTIONS net ${EXT_IF} detect dhcp,logmartians=1,blacklist dmz $DMZ_IF detect logmartians=1 loc $INT_IF detect dhcp,logmartians=1,routeback,bridge loc $TEST_IF detect optional loc $TEST1_IF detect optional wifi $WIFI_IF detect dhcp,maclist,mss=1400 vpn tun+ -
/etc/shorewall/nat:#EXTERNAL INTERFACE INTERNAL ALLINTS LOCAL COMMENT One-to-one NAT 206.124.146.178 $EXT_IF:0 192.168.1.3 No No 206.124.146.180 $EXT_IF:2 192.168.1.6 No No
/etc/shorewall/masq (Note the cute trick here and in the. The leading "+" is required to place the rule before the SNAT rules generated by entries infollowing proxyarpfile that allows me to access the DSL "Modem" using its default IP address (192.168.1.1))/etc/shorewall/natabove.#INTERFACE SOURCE ADDRESS PROTO DPORT IPSEC COMMENT Handle DSL 'Modem' +$EXT_IF:192.168.1.1 0.0.0.0/0 192.168.1.254 COMMENT Masquerade VPN clients and Wifi $EXT_IF 192.168.2.0/24 $EXT_IF 192.168.3.0/24 $EXT_IF:192.168.98.1 192.168.99.1 192.168.1.99 $EXT_IF:192.168.99.1 192.168.98.1 192.168.1.98 COMMENT Masquerade Local Network $EXT_IF 192.168.1.0/24 206.124.146.179
/etc/shorewall/proxyarp:#ADDRESS INTERFACE EXTERNAL HAVEROUTE PERSISTENT 192.168.1.1 $EXT_IF $INT_IF yes 206.124.146.177 $DMZ_IF $EXT_IF yes 192.168.1.7 $TEST_IF $INT_IF yes
/etc/shorewall/tunnels:#TYPE ZONE GATEWAY GATEWAY_ZONE openvpnserver:udp net 0.0.0.0/0 #Routed server for RoadWarrior access openvpnserver:udp wifi 192.168.3.0/24 #Home wireless network server
/etc/shorewall/actions:#ACTION Mirrors # Accept traffic from Shorewall Mirrors
/etc/shorewall/action.Mirrors:#TARGET SOURCE DEST PROTO DPORT SPORT ORIGDEST RATE ACCEPT $MIRRORS
/etc/shorewall/rules:SECTION NEW ############################################################################################################################################################################### #ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST RATE USER ############################################################################################################################################################################### REJECT:$LOG loc net tcp 25 REJECT:$LOG loc net udp 1025:1031 # # Stop NETBIOS crap # REJECT loc net tcp 137,445 REJECT loc net udp 137:139 # # Stop my idiotic work laptop from sending to the net with an HP source/dest IP address # DROP loc:!192.168.0.0/22 net ############################################################################################################################################################################### # Local Network to Firewall # REDIRECT- loc 3128 tcp 80 - !192.168.1.1,192.168.0.7,206.124.146.177,155.98.64.80 ############################################################################################################################################################################### # Road Warriors to Firewall # ACCEPT vpn fw tcp ssh,time,631,8080 ACCEPT vpn fw udp 161,ntp,631 Ping(ACCEPT) vpn fw ############################################################################################################################################################################### # Road Warriors to DMZ # ACCEPT vpn dmz udp domain ACCEPT vpn dmz tcp www,smtp,smtps,domain,ssh,imap,https,imaps,ftp,10023,pop3 - Ping(ACCEPT) vpn dmz ############################################################################################################################################################################### # Local network to DMZ # ACCEPT loc dmz udp domain ACCEPT loc dmz tcp ssh,smtps,www,ftp,imaps,domain,https - ACCEPT loc dmz tcp smtp Trcrt(ACCEPT) loc dmz ############################################################################################################################################################################### # Internet to ALL -- drop NewNotSyn packets # dropNotSyn net fw tcp #dropNotSyn net loc tcp dropNotSyn net dmz tcp ############################################################################################################################################################################### # Internet to DMZ # ACCEPT net dmz udp domain LOG:$LOG net:64.126.128.0/18 dmz tcp smtp ACCEPT net dmz tcp smtps,www,ftp,imaps,domain,https - ACCEPT net dmz tcp smtp - 206.124.146.177,206.124.146.178 ACCEPT net dmz udp 33434:33454 Mirrors net dmz tcp rsync Limit:$LOG:SSHA,3,60\ net dmz tcp 22 Trcrt(ACCEPT) net dmz ############################################################################################################################################################################## # # Net to Local # # When I'm "on the road", the following two rules allow me VPN access back home using PPTP. # DNAT net loc:192.168.1.4 tcp 1729 DNAT net loc:192.168.1.4 gre # # Roadwarrior access to Ursa # ACCEPT net:$OMAK loc tcp 22 Limit:$LOG:SSHA,3,60\ net loc tcp 22 # # ICQ # ACCEPT net loc:192.168.1.3 tcp 113,4000:4100 # # Bittorrent # ACCEPT net loc:192.168.1.3 tcp 6881:6889,6969 ACCEPT net loc:192.168.1.3 udp 6881:6889,6969 # # Real Audio # ACCEPT net loc:192.168.1.3 udp 6970:7170 # # Overnet # #ACCEPT net loc:192.168.1.3 tcp 4662 #ACCEPT net loc:192.168.1.3 udp 12112 # # OpenVPN # ACCEPT net loc:192.168.1.3 udp 1194 ACCEPT net loc:192.168.1.6 udp 1194 # Skype # ACCEPT net loc:192.168.1.6 tcp 1194 # # Traceroute # Trcrt(ACCEPT) net loc:192.168.1.3 # # Silently Handle common probes # REJECT net loc tcp www,ftp,https DROP net loc icmp 8 ############################################################################################################################################################################### # DMZ to Internet # ACCEPT dmz net udp domain,ntp ACCEPT dmz net tcp echo,ftp,ssh,smtp,whois,domain,www,81,https,cvspserver,2702,2703,8080 ACCEPT dmz net:$POPSERVERS tcp pop3 Ping(ACCEPT) dmz net # # Some FTP clients seem prone to sending the PORT command split over two packets. This prevents the FTP connection tracking # code from processing the command and setting up the proper expectation. The following rule allows active FTP to work in these cases # but logs the connection so I can keep an eye on this potential security hole. # ACCEPT:$LOG dmz net tcp 1024: 20 ############################################################################################################################################################################### # Local to DMZ # ACCEPT loc dmz udp domain,xdmcp ACCEPT loc dmz tcp www,smtp,smtps,domain,ssh,imap,rsync,https,imaps,ftp,10023,pop3,3128 Trcrt(ACCEPT) loc dmz ############################################################################################################################################################################### # DMZ to Local # ACCEPT dmz loc:192.168.1.5 udp 123 ACCEPT dmz loc:192.168.1.5 tcp 21 Ping(ACCEPT) dmz loc ############################################################################################################################################################################### # DMZ to Firewall -- ntp & snmp, Silently reject Auth # #ACCEPT net loc:192.168.1.3 udp 12112 # # OpenVPN # ACCEPT net loc:192.168.1.3 udp 1194 ACCEPT net loc:192.168.1.6 udp 1194 # Skype # ACCEPT net loc:192.168.1.6 tcp 1194 # # Traceroute # Trcrt(ACCEPT) net loc:192.168.1.3 # # Silently Handle common probes # REJECT net loc tcp www,ftp,https DROP net loc icmp 8 ############################################################################################################################################################################### # DMZ to Internet # ACCEPT dmz net udp domain,ntp ACCEPT dmz net tcp echo,ftp,ssh,smtp,whois,domain,www,81,https,cvspserver,2702,2703,8080 ACCEPT dmz net:$POPSERVERS tcp pop3 Ping(ACCEPT) dmz net # # Some FTP clients seem prone to sending the PORT command split over two packets. This prevents the FTP connection tracking # code from processing the command and setting up the proper expectation. The following rule allows active FTP to work in these cases # but logs the connection so I can keep an eye on this potential security hole. # ACCEPT:$LOG dmz net tcp 1024: 20 ############################################################################################################################################################################### # Local to DMZ # ACCEPT loc dmz udp domain,xdmcp ACCEPT loc dmz tcp www,smtp,smtps,domain,ssh,imap,rsync,https,imaps,ftp,10023,pop3,3128 Trcrt(ACCEPT) loc dmz ############################################################################################################################################################################### # DMZ to Local # ACCEPT dmz loc:192.168.1.5 udp 123 ACCEPT dmz loc:192.168.1.5 tcp 21 Ping(ACCEPT) dmz loc ############################################################################################################################################################################### # DMZ to Firewall -- ntp & snmp, Silently reject Auth # ACCEPT loc dmz udp domain,xdmcp ACCEPT loc dmz tcp www,smtp,smtps,domain,ssh,imap,rsync,https,imaps,ftp,10023,pop3,3128 Trcrt(ACCEPT) loc dmz ############################################################################################################################################################################### # DMZ to Local # ACCEPT dmz loc:192.168.1.5 udp 123 ACCEPT dmz loc:192.168.1.5 tcp 21 Ping(ACCEPT) dmz loc ############################################################################################################################################################################### # DMZ to Firewall -- ntp & snmp, Silently reject Auth # ACCEPT dmz fw tcp 161,ssh ACCEPT dmz fw udp 161,ntp REJECT dmz fw tcp auth Ping(ACCEPT) dmz fw ############################################################################################################################################################################### # Internet to Firewall # REJECT net fw tcp www,ftp,https DROP net fw icmp 8 ACCEPT net fw udp 33434:33454 ACCEPT net:$OMAK fw udp ntp ACCEPT net fw tcp auth ACCEPT net:$OMAK fw tcp 22 Limit:$LOG:SSHA,3,60\ net fw tcp 22 Trcrt(ACCEPT) net fw # # Bittorrent # ACCEPT net fw tcp 6881:6889,6969 ACCEPT net fw udp 6881:6889,6969 ############################################################################################################################################################################### # Firewall to DMZ # ACCEPT fw dmz tcp domain,www,ftp,ssh,smtp,https,993,465 ACCEPT fw dmz udp domain REJECT fw dmz udp 137:139 Ping(ACCEPT) fw dmz ############################################################################################################################################################################## # Avoid logging Freenode.net probes # DROP net:82.96.96.3 all
etc/shorewall/tcdevices#INTERFACE IN_BANDWITH OUT_BANDWIDTH $EXT_IF 1300kbit 384kbit
/etc/shorewall/tcclasses#INTERFACE MARK RATE CEIL PRIORITY OPTIONS $EXT_IF 10 5*full/10 full 1 tcp-ack,tos-minimize-delay $EXT_IF 20 3*full/10 9*full/10 2 default $EXT_IF 30 2*full/10 6*full/10 3
/etc/shorewall/mangle#ACTION SOURCE DEST PROTO DPORT SPORT USER TEST CLASSIFY(1:110) 192.168.0.0/22 $EXT_IF #Our internal nets get priority #over the server CLASSIFY(1:130) 206.124.146.177 $EXT_IF tcp - 873 #Throttle rsync traffic to the #Shorewall Mirrors.
The tap0 device used by
the bridged OpenVPN server is created and bridged to eth1 using a SUSE-specific SysV init
script:
#!/bin/sh
#
# The Shoreline Firewall (Shorewall) Packet Filtering Firewall - V3.0
#
# This program is under GPL [http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt]
#
# (c) 1999,2000,2001,2002,2003,2004,2005 - Tom Eastep (teastep@shorewall.net)
#
# On most distributions, this file should be called /etc/init.d/shorewall.
#
# Complete documentation is available at https://shorewall.org
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of Version 2 of the GNU General Public License
# as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# If an error occurs while starting or restarting the firewall, the
# firewall is automatically stopped.
#
# Commands are:
#
# bridge start Starts the bridge
# bridge restart Restarts the bridge
# bridge reload Restarts the bridge
# bridge stop Stops the bridge
# bridge status Displays bridge status
#
# chkconfig: 2345 4 99
# description: Packet filtering firewall
### BEGIN INIT INFO
# Provides: bridge
# Required-Start: boot.udev
# Required-Stop:
# Default-Start: 2 3 5
# Default-Stop: 0 1 6
# Description: starts and stops the bridge
### END INIT INFO
################################################################################
# Interfaces to be bridged -- may be listed by device name or by MAC
#
INTERFACES="eth1"
#
# Tap Devices
#
TAPS="tap0"
################################################################################
# Give Usage Information #
################################################################################
usage() {
echo "Usage: $0 start|stop|reload|restart|status"
exit 1
}
#################################################################################
# Find the interface with the passed MAC address
#################################################################################
find_interface_by_mac() {
local mac
mac=$1
local first
local second
local rest
local dev
/sbin/ip link ls | while read first second rest; do
case $first in
*:)
dev=$second
;;
*)
if [ "$second" = $mac ]; then
echo ${dev%:}
return
fi
esac
done
}
################################################################################
# Convert MAC addresses to interface names
################################################################################
get_interfaces() {
local interfaces
interfaces=
local interface
for interface in $INTERFACES; do
case $interface in
*:*:*)
interface=$(find_interface_by_mac $interface)
[ -n "$interface" ] || echo "WARNING: Can't find an interface with MAC address $mac"
;;
esac
interfaces="$interfaces $interface"
done
INTERFACES="$interfaces"
}
################################################################################
# Start the Bridge
################################################################################
do_start()
{
local interface
get_interfaces
for interface in $TAPS; do
/usr/sbin/openvpn --mktun --dev $interface
done
/sbin/brctl addbr br0
for interface in $INTERFACES $TAPS; do
/sbin/ip link set $interface up
/sbin/brctl addif br0 $interface
done
}
################################################################################
# Stop the Bridge
################################################################################
do_stop()
{
local interface
get_interfaces
for interface in $INTERFACES $TAPS; do
/sbin/brctl delif br0 $interface
/sbin/ip link set $interface down
done
/sbin/ip link set br0 down
/sbin/brctl delbr br0
for interface in $TAPS; do
/usr/sbin/openvpn --rmtun --dev $interface
done
}
################################################################################
# E X E C U T I O N B E G I N S H E R E #
################################################################################
command="$1"
case "$command" in
start)
do_start
;;
stop)
do_stop
;;
restart|reload)
do_stop
do_start
;;
status)
/sbin/brctl show
;;
*)
usage
;;
esac