cleanup ips detection

[pve-firewall.git] / README

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-Experimental software, only used for testing.
+Experimental software, only used for testing!
+=============================================
+
+
+Quick Intro
+===========
 
 VM firewall rules are read from /etc/pve/firewall/<VMID>.fw
 
+Security group rules are read from /etc/pve/firewall/groups.fw
+
+Host firewall rules are read from /etc/pve/local/host.fw
+
 You can find examples in the example/ dir
 
-Use the following command to generate shorewall configuration:
+
+Use the following command to mange the firewall:
+
+To test the firewall configuration:
 
 ./pvefw compile
 
-That command overwrites /etc/shorewall/, so don't use if you have
-and existing shorewall config you want to keep.
+To start or update the firewall:
+
+./pvefw start
+
+To update the firewall rules (the firewall is not started if it
+is not already running):
+
+./pvefw update
+
+To stop the firewall:
+
+./pvefw stop
+
+
+Implementation details
+======================
+
+We write iptables rules directly, an generate the following chains 
+as entry points in the 'forward' table:
+
+PVEFW-INPUT
+PVEFW-OUTPUT
+PVEFW-FORWARD
+
+We do not touch other (user defined) chains.
+
+Each VM can have its own firewall definition file in 
+
+/etc/pve/firewall/<VMID>.fw
+
+That file has a section [RULES] to define firewall rules.
+
+Format is: TYPE ACTION IFACE SOURCE DEST PROTO D-PORT S-PORT
+
+* TYPE: IN|OUT|GROUP 
+* ACTION: action or macro
+* IFACE: vm network interface (net0 - net5), or '-' for all interfaces
+* SOURCE: source IP address, or '-' for any source
+* DEST: dest IP address, or '-' for any destination address
+* PROTO: see /etc/protocols
+* D-PORT: destination port
+* S-PORT: source port
+
+A rule for inbound traffic looks like this:
+
+IN SSH(ACCEPT) net0
+
+Outbound rules looks like:
+
+OUT SSH(ACCEPT)
+
+Problems
+===================
+
+There are a number of restrictions when using iptables to filter
+bridged traffic. The physdev match feature does not work correctly
+when traffic is routed from host to bridge:
+
+  * when a packet being sent through a bridge entered the firewall on another interface 
+    and was being forwarded to the bridge.
+
+  * when a packet originating on the firewall itself is being sent through a bridge.
+
+So we disable the firewall if we detect such case (bridge with assigned IP address).
+You can enable it again (if you do not care) by setting "allow_bridge_route: 1" in "host.fw".
+
+The correct workaround is to remove the IP address from the bridge device, and
+use a veth device which is plugged into the bridge:
+
+---/etc/network/interfaces----
+
+...
+
+auto vmbr0
+iface vmbr0 inet manual
+       bridge_ports bond0
+       bridge_stp off
+       bridge_fd 0
+
+# this create the veth device and plug it into vmbr0
+auto pm0
+iface pm0 inet static
+       address  192.168.10.10
+       netmask  255.255.255.0
+       gateway  192.168.10.1
+       VETH_BRIDGETO vmbr0
+
+auto vmbr1
+iface vmbr1 inet manual
+      bridge_ports none
+      bridge_stp off
+      bridge_fd 0
+
+# setup masqueraded bridge port vmbr1/pm1 using pm0
+# NOTE: this needs kernel 3.10.0 or newer (for conntrack --zone) 
+auto pm1
+iface pm1 inet static
+       address 10.10.10.1
+       netmask 255.255.255.0
+       VETH_BRIDGETO vmbr1
+       VETH_MASQUERADE pm0
+
+...
+
+--------------------------------