Summary
I am currently working on a three interface software firewall using Shorewall 4.5.5.3 on Debian Wheezy, and I'm having some difficulty with the loc (eth2) and dmz (eth1) interfaces. The fw (eth0) interface seems to be working just fine, but I cannot ping PCs on loc or dmz zones. There is likely something wrong with my /etc/network/interfaces setup in the network.
The fw interface runs on dhcp through my ISP, and I configured the loc and dmz interfaces and PCs inside those zones with static IPs. The configuration that I'm trying to use is the three-interface and single IP configuration. The reference document is located on the Shorewall website, "Three-Interface Firewall". I don't know what to do about a gateway on eth1 or eth2 interfaces, b/c the Shorewall docs don't explain that. I assume it would be the same gateway as eth0, but I don't know how to do that since eth0 is on dhcp.
Networking
/etc/network/interfaces for firmware node:
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto eth0
iface eth0 inet dhcp
# Secondary network interface for dmz
auto eth1
iface eth1 inet static
address 10.10.1.1/24
netmask 255.255.255.0
# Tirtirary network interface for loc
auto eth2
iface eth2 inet static
address 10.10.2.1/24
netmask 255.255.255.0
/etc/network/interfaces for dmz
# dmz network interface
auto eth0
iface eth0 inet static
address 10.10.1.2/24
netmask 255.255.255.0
gateway 10.10.1.1
Starting with just the dmz, is there something wrong with my network interfaces setup?
This is what happens when i restart my networking:
Listening on LPF/eth0/HEX:...:...
Sending on LPF/eth0/HEX:...:...
Sending on Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6
DHCPREQUEST on eth0 to 255.255.255.255 port 67
DHCPOFFER from XY.IP...
DHCPACK from XY.IP...
suspect value in ^1/7078C526/res-5000-2.0 option - discarded
suspect value in ^1/FBEA1017/res-5000-2.0 option - discarded
bound to NEW.IP... -- renewal in 33594 seconds.
done.
I don't understand the "suspect .... - discarded" lines. Does this indicate a problem, or are those potential IPs that are being rejected?
These are the results of ifconfig:
eth0 Link encap:Ethernet HWaddr MAC
inet addr:DHCP.IP Bcast:DHCP.BC Mask:DHCP.M
inet6 addr: inet6.IP Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:268607 errors:0 dropped:0 overruns:0 frame:0
TX packets:89830 errors:0 dropped:0 overruns:0 carrier:7
collisions:0 txqueuelen:1000
RX bytes:25066229 (23.9 MiB) TX bytes:10734393 (10.2 MiB)
Interrupt:17
eth1 Link encap:Ethernet HWaddr c0:4a:00:03:00:04
inet addr:10.10.1.1 Bcast:10.10.1.255 Mask:255.255.255.0
inet6 addr: fe80::c24a:ff:fe03:4/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:82 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:4664 (4.5 KiB)
Interrupt:19 Base address:0xac00
eth2 Link encap:Ethernet HWaddr c0:4a:00:07:6a:31
inet addr:10.10.2.1 Bcast:10.10.2.255 Mask:255.255.255.0
inet6 addr: fe80::c24a:ff:fe07:6a31/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:48 errors:0 dropped:0 overruns:0 frame:0
TX packets:33 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2880 (2.8 KiB) TX bytes:2578 (2.5 KiB)
Interrupt:16 Base address:0xe800
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:41 errors:0 dropped:0 overruns:0 frame:0
TX packets:41 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4592 (4.4 KiB) TX bytes:4592 (4.4 KiB)
Shorewall settings
interfaces
net eth0 tcpflags,dhcp,nosmurfs,routefilter,logmartians,sourceroute=0
dmz eth1 tcpflags,nosmurfs,routefilter,logmartians
loc eth2 tcpflags,nosmurfs,routefilter,logmartians
masq
eth0 10.10.1.0/24
eth0 10.10.2.0/24
params
ETH0_IP=$(find_first_interface_address eth0)
policy
loc net ACCEPT
net all DROP info
# THE FOLLOWING POLICY MUST BE LAST
all all REJECT info
routestopped
eth1 -
eth2 -
rules
SECTION NEW
# Don't allow connection pickup from the net
Invalid(DROP) net all
# Accept DNS connections from the firewall to the Internet
DNS(ACCEPT) $FW net
# Accept SSH connections from the local network to the firewall and DMZ
SSH(ACCEPT) loc $FW
SSH(ACCEPT) loc dmz
# DMZ DNS access to the Internet
DNS(ACCEPT) dmz net
# Drop Ping from the "bad" net zone.
Ping(DROP) net $FW
# Make ping work bi-directionally between the dmz, net, Firewall and local zone
# (assumes that the loc-> net policy is ACCEPT).
Ping(ACCEPT) loc $FW
Ping(ACCEPT) dmz $FW
Ping(ACCEPT) loc dmz
Ping(ACCEPT) dmz loc
Ping(ACCEPT) dmz net
Ping(ACCEPT) loc net
ACCEPT $FW net icmp
ACCEPT $FW loc icmp
ACCEPT $FW dmz icmp
# Allow connection to web server from loc to dmz
DNAT loc dmz:10.10.1.2 tcp - 80,443 $ETH0_IP
# Allow DNS connection to internal server from net
DNS(ACCEPT) loc dmz:10.10.1.3
DNS(ACCEPT) $FW dmz:10.10.1.3
DNS(ACCEPT) loc dmz:10.10.1.4
DNS(ACCEPT) $FW dmz:10.10.1.4
# Allow SMTPS traffic to internal server from net
SMTPS(ACCEPT) dmz:10.10.1.2 $FW
POP3S(ACCEPT) $FW dmz:10.10.1.2
# Allow SSH and SFTP on web server
SSH(ACCEPT) $FW dmz:10.10.1.2
SSH(ACCEPT) net $FW
shorewall.conf
# Only change in this file:
IP_FORWARDING=On
zones
fw firewall
net ipv4
loc ipv4
dmz ipv4
shorewall check
Checking...
Processing /etc/shorewall/params ...
Processing /etc/shorewall/shorewall.conf...
Loading Modules...
Checking /etc/shorewall/zones...
Checking /etc/shorewall/interfaces...
Determining Hosts in Zones...
Locating Action Files...
Checking /usr/share/shorewall/action.Drop for chain Drop...
Checking /usr/share/shorewall/action.Broadcast for chain Broadcast...
Checking /usr/share/shorewall/action.Invalid for chain Invalid...
Checking /usr/share/shorewall/action.NotSyn for chain NotSyn...
Checking /usr/share/shorewall/action.Reject for chain Reject...
Checking /etc/shorewall/policy...
Adding Anti-smurf Rules
Adding rules for DHCP
Checking TCP Flags filtering...
Checking Kernel Route Filtering...
Checking Martian Logging...
Checking Accept Source Routing...
Checking /etc/shorewall/masq...
Checking MAC Filtration -- Phase 1...
Checking /etc/shorewall/rules...
Checking /usr/share/shorewall/action.Invalid for chain %Invalid...
Checking MAC Filtration -- Phase 2...
Applying Policies...
Checking /etc/shorewall/routestopped...
Shorewall configuration verified
shorewall start
Compiling...
Processing /etc/shorewall/params ...
Processing /etc/shorewall/shorewall.conf...
Loading Modules...
Compiling /etc/shorewall/zones...
Compiling /etc/shorewall/interfaces...
Determining Hosts in Zones...
Locating Action Files...
Compiling /usr/share/shorewall/action.Drop for chain Drop...
Compiling /usr/share/shorewall/action.Broadcast for chain Broadcast...
Compiling /usr/share/shorewall/action.Invalid for chain Invalid...
Compiling /usr/share/shorewall/action.NotSyn for chain NotSyn...
Compiling /usr/share/shorewall/action.Reject for chain Reject...
Compiling /etc/shorewall/policy...
Adding Anti-smurf Rules
Adding rules for DHCP
Compiling TCP Flags filtering...
Compiling Kernel Route Filtering...
Compiling Martian Logging...
Compiling Accept Source Routing...
Compiling /etc/shorewall/masq...
Compiling MAC Filtration -- Phase 1...
Compiling /etc/shorewall/rules...
Compiling /usr/share/shorewall/action.Invalid for chain %Invalid...
Compiling MAC Filtration -- Phase 2...
Applying Policies...
Generating Rule Matrix...
Creating iptables-restore input...
Compiling /etc/shorewall/routestopped...
Shorewall configuration compiled to /var/lib/shorewall/.start
Starting Shorewall....
Initializing...
Setting up Route Filtering...
Setting up Martian Logging...
Setting up Accept Source Routing...
Setting up Traffic Control...
Preparing iptables-restore input...
Running /sbin/iptables-restore...
IPv4 Forwarding Enabled
done.
Ping
in fw terminal: ping 10.10.1.2
PING 10.10.1.2 (10.10.1.2) 56(84) bytes of data.
From 10.10.1.1 icmp_seq=1 Destination Host Unreachable
From 10.10.1.1 icmp_seq=2 Destination Host Unreachable
From 10.10.1.1 icmp_seq=3 Destination Host Unreachable
in dmz terminal: ping 10.10.1.1
connect: network not reachable
I don't know what is missing/wrong. Any help would be appreciated.
