debian/README

   1 Experimental software, only used for testing!
   2 =============================================
   3
   4
   5 Quick Intro
   6 ===========
   7
   8 VM firewall rules are read from:
   9
  10  /etc/pve/firewall/<VMID>.fw
  11
  12 Cluster wide rules and security group are read from:
  13
  14  /etc/pve/firewall/cluster.fw
  15
  16 Host firewall rules are read from:
  17
  18   /etc/pve/local/host.fw
  19
  20 You can find examples in the example/ dir
  21
  22
  23 Use the following command to mange the firewall:
  24
  25 To test the firewall configuration:
  26
  27 ./pvefw compile
  28
  29 To start or update the firewall:
  30
  31 ./pvefw start
  32
  33 To update the firewall rules (the firewall is not started if it
  34 is not already running):
  35
  36 ./pvefw update
  37
  38 To stop the firewall:
  39
  40 ./pvefw stop
  41
  42
  43 Implementation details
  44 ======================
  45
  46 We write iptables rules directly, an generate the following chains
  47 as entry points in the 'forward' table:
  48
  49 PVEFW-INPUT
  50 PVEFW-OUTPUT
  51 PVEFW-FORWARD
  52
  53 We do not touch other (user defined) chains.
  54
  55 Each VM can have its own firewall definition file in
  56
  57 /etc/pve/firewall/<VMID>.fw
  58
  59 That file has a section [RULES] to define firewall rules.
  60
  61 Format is: TYPE ACTION IFACE SOURCE DEST PROTO D-PORT S-PORT
  62
  63 * TYPE: IN|OUT|GROUP
  64 * ACTION: action or macro
  65 * IFACE: vm network interface (net0 - net5), or '-' for all interfaces
  66 * SOURCE: source IP address, or '-' for any source
  67 * DEST: dest IP address, or '-' for any destination address
  68 * PROTO: see /etc/protocols
  69 * D-PORT: destination port
  70 * S-PORT: source port
  71
  72 A rule for inbound traffic looks like this:
  73
  74 IN SSH(ACCEPT) net0
  75
  76 Outbound rules looks like:
  77
  78 OUT SSH(ACCEPT)
  79
  80 Problems
  81 ===================
  82
  83 There are a number of restrictions when using iptables to filter
  84 bridged traffic. The physdev match feature does not work correctly
  85 when traffic is routed from host to bridge:
  86
  87   * when a packet being sent through a bridge entered the firewall on
  88     another interface and was being forwarded to the bridge.
  89
  90   * when a packet originating on the firewall itself is being sent through
  91     a bridge.
  92
  93 We use a second bridge for each interface to avoid above problem.
  94
  95 eth0-->vmbr0<--tapXiY (non firewalled tap)
  96             <--linkXiY-->linkXiYp-->fwbrXiY-->tapXiY (firewalled tap)