Shorewall: Difference between revisions

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make the following edits to the following files and then copy them to /etc/shorewall
make the following edits to the following files and then copy them to /etc/shorewall


rules
== policy ==
You may want to allow everything from the local network to the machine and everything from the machine to the net, as well as everything from the machine to the local network in that case add the following to the policy file:
<pre>
loc            fw              ACCEPT
fw              net            ACCEPT
fw              loc            ACCEPT
</pre>
 
If it's a router it would look something like:
<pre>
loc            net            ACCEPT
net            all            DROP            info
fw              all            ACCEPT
loc            all            ACCEPT
# THE FOLLOWING POLICY MUST BE LAST
all            all            REJECT          info
</pre>
 
== rules ==
'''Allready includes the following'''
<pre>
?SECTION NEW
 
#      Don't allow connection pickup from the net
#
Invalid(DROP)  net            all
#
#      Accept DNS connections from the firewall to the network
#
DNS(ACCEPT)    $FW            net
#
#      Accept SSH connections from the local network for administration
#
SSH(ACCEPT)    loc            $FW
SNMP(ACCEPT)    loc            $FW
#
#      Allow Ping from the local network
#
Ping(ACCEPT)    loc            $FW
 
#
# Drop Ping from the "bad" net zone.. and prevent your log from being flooded..
#
 
Ping(DROP)      net            $FW
 
ACCEPT          $FW            loc            icmp
ACCEPT          $FW            net            icmp
#
</pre>
 
So the following needs to be added:
NOTE: snmp should only be udp 161, so not sure if tcp is necessary
 
<pre>
<pre>
SNMP(ACCEPT)    loc            $FW
SNMP(ACCEPT)    loc            $FW
Line 19: Line 72:
ACCEPT  net    fw      tcp    snmp
ACCEPT  net    fw      tcp    snmp
ACCEPT  net    fw      udp    snmp
ACCEPT  net    fw      udp    snmp
</pre>
Also, apt uses port 80, so you want to allow outgoing traffic for that:
<pre>
ACCEPT  $FW    net    tcp    http
</pre>
If you don't do this then you will see ipv6 adresses appear in apt-get
Other services you may want to enable from the machine outwards:
<pre>
# Things we allow from this machine outward
ACCEPT  $FW    net    tcp    https
SSH(ACCEPT)    $FW    loc
ACCEPT  $FW    net    tcp    smtp
</pre>
For X11 forwarding you will need:
<pre>
# X11 forwarding
# X11 forwarding
ACCEPT  fw    loc    tcp    x11
ACCEPT  fw    loc    tcp    x11
Line 24: Line 95:
</pre>
</pre>


You may want other machines on the local network to access more services:
<pre>
# Things we accept over the local network
FTP/ACCEPT      loc    $FW
ACCEPT  loc    $FW    tcp    http
</pre>
== interfaces ==
If you have multiple ip addresses bound to a single NIC, in order to allow traffic to flow up and down that NIC, you have to add the option
<pre>
routeback
</pre>
behind the nic.
== the rest ==
just copy the following files to /etc/shorewall/:
just copy the following files to /etc/shorewall/:
<pre>
<pre>
interfaces
masq
masq
policy
routestopped
routestopped
zones
zones
</pre>
</pre>


/etc/default/shorewall
== /etc/default/shorewall ==
</pre>
<pre>
startup=1
startup=1
</pre>
</pre>
Line 108: Line 193:
= Shorewall6 =
= Shorewall6 =


http://tldp.org/HOWTO/Linux+IPv6-HOWTO/
http://www.shorewall.net/IPv6Support.html
http://www.shorewall.net/IPv6Support.html


Shorewall6 is the ipv6 version of shorewall. To get it working you need to do above steps and also:
Shorewall6 is the ipv6 version of shorewall. To get it working you need to do above steps and also:
Make sure you have a valid IPv6 address connected to your NICs.
Because we have no valid ipv6 from KPN yet, we use a 6to4 tunnelling address, which always start with 2002:
In order to calculate the ipv6 from the ipv4 address we need:
<pre>
ipv6calc --quiet --action conv6to4 188.204.140.215
</pre>
or
<pre>
ipv4="1.2.3.4"; printf "2002:%02x%02x:%02x%02x::1" `echo $ipv4 | tr "." " "`
</pre>
This gives:
<pre>
2002:bccc:8cd7::
</pre>
so in /etc/network/interfaces add something like
<pre>
iface eth0 inet6 static
        address 2002:bccc:8cd7::1
        netmask 64
</pre>
underneath your ipv4 network interfaces. NOTE: Notice the '1' at the end! (see also 3.2.4.2 in http://tldp.org/HOWTO/Linux+IPv6-HOWTO/x513.html)
Now we need to bring up a ipv6 to ipv4 tunnel http://tldp.org/HOWTO/Linux+IPv6-HOWTO/configuring-ipv6to4-tunnels.html:
<pre>
ip tunnel add tun6to4 mode sit ttl 255 remote any local 188.204.140.215
ip link set dev tun6to4 up
ip -6 addr add 2002:bccc:8cd7::1/16 dev tun6to4
ip -6 route add 2000::/3 via ::188.204.140.193 dev tun6to4 metric 1
</pre>
which we can test with:
<pre>
ping6 ipv6.google.com
</pre>


in /etc/shorewall/shorewall.conf
in /etc/shorewall/shorewall.conf
Line 168: Line 213:
</pre>
</pre>


= Single NIC Machine  
= Single NIC Machine =
<pre>=
 
NOTE: snmp should only be udp 161, so not sure if tcp is necessary
<pre>
/etc/default/shorewall
/etc/default/shorewall
Set startup=1
Set startup=1
Line 215: Line 262:
(above fw      firewall)
(above fw      firewall)
</pre>
</pre>
= testing =
shorewall check

Latest revision as of 18:43, 30 May 2022

2 NIC machine

In /usr/share/doc/shorewall/examples/two-interfaces make the following edits to the following files and then copy them to /etc/shorewall

policy

You may want to allow everything from the local network to the machine and everything from the machine to the net, as well as everything from the machine to the local network in that case add the following to the policy file: 

loc             fw              ACCEPT
fw              net             ACCEPT
fw              loc             ACCEPT

If it's a router it would look something like: 

loc             net             ACCEPT
net             all             DROP            info
fw              all             ACCEPT
loc             all             ACCEPT
# THE FOLLOWING POLICY MUST BE LAST
all             all             REJECT          info

rules

Allready includes the following 

?SECTION NEW

#       Don't allow connection pickup from the net
#
Invalid(DROP)   net             all
#
#       Accept DNS connections from the firewall to the network
#
DNS(ACCEPT)     $FW             net
#
#       Accept SSH connections from the local network for administration
#
SSH(ACCEPT)     loc             $FW
SNMP(ACCEPT)    loc             $FW
#
#       Allow Ping from the local network
#
Ping(ACCEPT)    loc             $FW

#
# Drop Ping from the "bad" net zone.. and prevent your log from being flooded..
#

Ping(DROP)      net             $FW

ACCEPT          $FW             loc             icmp
ACCEPT          $FW             net             icmp
#

So the following needs to be added: NOTE: snmp should only be udp 161, so not sure if tcp is necessary 

SNMP(ACCEPT)    loc             $FW
# Public services
ACCEPT   net    fw      tcp     smtp
ACCEPT   net    fw      tcp     pop3
# 143 is for IMAP
ACCEPT  net     fw      tcp     143
ACCEPT   net    fw      tcp     ssh
FTP/ACCEPT      net     fw
ACCEPT   net    fw      tcp     domain
ACCEPT   net    fw      udp     domain
ACCEPT   net    fw      tcp     http
ACCEPT   net    fw      tcp     https
ACCEPT   net    fw      tcp     snmp
ACCEPT   net    fw      udp     snmp

Also, apt uses port 80, so you want to allow outgoing traffic for that: 

ACCEPT  $FW     net     tcp     http

If you don't do this then you will see ipv6 adresses appear in apt-get

Other services you may want to enable from the machine outwards: 

# Things we allow from this machine outward
ACCEPT  $FW     net     tcp     https
SSH(ACCEPT)     $FW     loc
ACCEPT  $FW     net     tcp     smtp

For X11 forwarding you will need: 

# X11 forwarding
ACCEPT   fw     loc     tcp     x11
ACCEPT   fw     loc     udp     x11

You may want other machines on the local network to access more services: 

# Things we accept over the local network
FTP/ACCEPT      loc     $FW
ACCEPT  loc     $FW     tcp     http

interfaces

If you have multiple ip addresses bound to a single NIC, in order to allow traffic to flow up and down that NIC, you have to add the option 

routeback

behind the nic.

the rest

just copy the following files to /etc/shorewall/: 

masq
routestopped
zones

/etc/default/shorewall

startup=1

To get NFS working

On nfs-kernel-server machine: Edit your /etc/shorewall/rules file like this: 

 # Permit NFS
 ACCEPT net $FW tcp 111
 ACCEPT net $FW udp 111
 ACCEPT net $FW udp 2049
 ACCEPT net $FW tcp 2049
 ACCEPT net $FW tcp 32765:32767
 ACCEPT net $FW udp 32765:32767

On nfs-common machine: 

# Permit NFS
ACCEPT $FW loc tcp 111
ACCEPT $FW loc udp 111
ACCEPT $FW loc udp 2049
ACCEPT $FW loc tcp 2049
ACCEPT $FW loc tcp 32765:32767
ACCEPT $FW loc udp 32765:32767

/etc/default/nfs-common: 

 STATDOPTS="-p 32765 -o 32766"

/etc/default/nfs-kernel-server: 

 RPCMOUNTDOPTS="-p 32767"

Make sure in your /etc/services you have the following 

 nfs     2049/tcp    # Network File System nfs     2049/udp    # Network File System


old system

The change to /etc/services isn't necessary at all. It just helps produces a nice (sensible) output from netstat -tl on the NFS server. 

 # /etc/services
 # NFS ports as per the NFS-HOWTO
 # http://www.tldp.org/HOWTO/NFS-HOWTO/security.html#FIREWALLS
 # Listing here does not mean they will bind to these ports. 
 rpc.nfsd        2049/tcp                        # RPC nfsd
 rpc.nfsd        2049/udp                        # RPC nfsd
 rpc.statd-bc    32765/tcp                       # RPC statd broadcast
 rpc.statd-bc    32765/udp                       # RPC statd broadcast
 rpc.statd       32766/tcp                       # RPC statd listen
 rpc.statd       32766/udp                       # RPC statd listen
 rpc.mountd      32767/tcp                       # RPC mountd
 rpc.mountd      32767/udp                       # RPC mountd
 rcp.lockd       32768/tcp                       # RPC lockd/nlockmgr
 rcp.lockd       32768/udp                       # RPC lockd/nlockmgr
 rpc.quotad      32769/tcp                       # RPC quotad
 rpc.quotad      32769/udp                       # RPC quotad

/etc/default/quota 

 RPCRQUOTADOPTS="-p 32769"

You can check which ports are being used with 

rpcinfo -p

Shorewall6

http://www.shorewall.net/IPv6Support.html

Shorewall6 is the ipv6 version of shorewall. To get it working you need to do above steps and also:

in /etc/shorewall/shorewall.conf 

DISABLE_IPV6=No
TC_ENABLED=Internal

/etc/shorewall6/shorewall.conf 

TC_ENABLED=No

test using 

ip6tables -L

Single NIC Machine

NOTE: snmp should only be udp 161, so not sure if tcp is necessary 

/etc/default/shorewall
Set startup=1

In /usr/share/doc/shorewall-common/default-config
make the following edits to the following files and then copy them to /etc/shorewall

interfaces
net     eth1    82.94.91.79

modules
(no edits)

policy
fw      net     ACCEPT
net     all     DROP    info
all     all     REJECT  info

NB to drop logging, get rid of the 'info' and replace it with 'crit' or 'err' or get rid of it entirely

rules
(under SECTION NEW)
ACCEPT   net    fw      tcp     smtp
ACCEPT   net    fw      tcp     pop3
ACCEPT   net    fw      tcp     ssh
FTP/ACCEPT      net     fw
ACCEPT   net    fw      tcp     domain
ACCEPT   net    fw      udp     domain
ACCEPT   fw     net     udp     domain
ACCEPT   net    fw      tcp     http
ACCEPT   fw     net     tcp     http
ACCEPT   net    fw      tcp     https
ACCEPT   net    fw      tcp     snmp
ACCEPT   fw     net     tcp     snmp
ACCEPT   net    fw      udp     snmp
ACCEPT   fw     net     udp     snmp
ACCEPT  net     fw      tcp     143
ACCEPT  net     fw      udp     143

start
dmesg -n5

zones
net     ipv4
(above fw      firewall)

testing

shorewall check

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