ifdef::manvolnum[] PVE({manvolnum}) ================ include::attributes.txt[] NAME ---- pve-firewall - The PVE Firewall Daemon SYNOPSYS -------- include::pve-firewall.8-synopsis.adoc[] DESCRIPTION ----------- endif::manvolnum[] ifndef::manvolnum[] {pve} Firewall ============== include::attributes.txt[] endif::manvolnum[] // Copied from pve wiki: Revision as of 08:45, 9 November 2015 Proxmox VE Firewall provides an easy way to protect your IT infrastructure. You can easily setup firewall rules for all hosts inside a cluster, or define rules for virtual machines and containers. Features like firewall macros, security groups, IP sets and aliases help making that task easier. While all configuration is stored on the cluster file system, the iptables based firewall runs on each cluster node, and thus provides full isolation between virtual machines. The distributed nature of this system also provides much higher bandwidth than a central firewall solution. NOTE: If you enable the firewall, all traffic is blocked by default, except WebGUI(8006) and ssh(22) from your local network. Zones ----- The Proxmox VE firewall groups the network into the following logical zones: Host:: Traffic from/to a cluster node VM:: Traffic from/to a specific VM For each zone, you can define firewall rules for incoming and/or outgoing traffic. Ports used by Proxmox VE ------------------------ * Web interface: 8006 * VNC Web console: 5900-5999 * SPICE proxy: 3128 * sshd (used for cluster actions): 22 * rpcbind: 111 * corosync multicast (if you run a cluster): 5404, 5405 UDP Configuration ------------- All firewall related configuration is stored on the proxmox cluster file system. So those files are automatically distributed to all cluster nodes, and the 'pve-firewall' service updates the underlying iptables rules automatically on any change. Any configuration can be done using the GUI (i.e. Datacenter -> Firewall -> Options tab (tabs at the bottom of the page), or on a Node -> Firewall), so the following configuration file snippets are just for completeness. Cluster wide configuration is stored at: /etc/pve/firewall/cluster.fw The firewall is completely disabled by default, so you need to set the enable option here: ---- [OPTIONS] # enable firewall (cluster wide setting, default is disabled) enable: 1 ---- The cluster wide configuration can contain the following data: * IP set definitions * Alias definitions * Security group definitions * Cluster wide firewall rules for all nodes VM firewall configuration is read from: /etc/pve/firewall/.fw and contains the following data: * IP set definitions * Alias definitions * Firewall rules for this VM * VM specific options And finally, any host related configuration is read from: /etc/pve/nodes//host.fw This is useful if you want to overwrite rules from 'cluster.fw' config. You can also increase log verbosity, and set netfilter related options. Enabling the Firewall for VMs and Containers ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You need to enable the firewall on the virtual network interface configuration in addition to the general 'Enable Firewall' option in the 'Options' tab. Firewall Rules ~~~~~~~~~~~~~~ Firewall rules consists of a direction (`IN` or `OUT`) and an action (`ACCEPT`, `DENY`, `REJECT`). You can also specify a macro name. Macros contain predifined sets of rules and options. Rules can be disabled by prefixing them with '|'. .Firewall rules syntax ---- [RULES] DIRECTION ACTION [OPTIONS] |DIRECTION ACTION [OPTIONS] # disabled rule DIRECTION MACRO(ACTION) [OPTIONS] # use predefined macro ---- The following options can be used to refine rule matches. include::pve-firewall-rules-opts.adoc[] Here are some examples: ---- [RULES] IN SSH(ACCEPT) -i net0 IN SSH(ACCEPT) -i net0 # a comment IN SSH(ACCEPT) -i net0 -source 192.168.2.192 # only allow SSH from 192.168.2.192 IN SSH(ACCEPT) -i net0 -source 10.0.0.1-10.0.0.10 # accept SSH for ip range IN SSH(ACCEPT) -i net0 -source 10.0.0.1,10.0.0.2,10.0.0.3 #accept ssh for ip list IN SSH(ACCEPT) -i net0 -source +mynetgroup # accept ssh for ipset mynetgroup IN SSH(ACCEPT) -i net0 -source myserveralias #accept ssh for alias myserveralias |IN SSH(ACCEPT) -i net0 # disabled rule IN DROP # drop all incoming packages OUT ACCEPT # accept all outgoing packages ---- Security Groups ~~~~~~~~~~~~~~~ A security group is a collection of rules, defined at cluster level, which can be used in all VMs' rules. For example you can define a group named `webserver` with rules to open the http and https ports. ---- # /etc/pve/firewall/cluster.fw [group webserver] IN ACCEPT -p tcp -dport 80 IN ACCEPT -p tcp -dport 443 ---- Then, you can add this group to a VM's firewall ---- # /etc/pve/firewall/.fw [RULES] GROUP webserver ---- IP Aliases ~~~~~~~~~~ IP Aliases allow you to associate IP addresses of networks with a name. You can then refer to those names: * inside IP set definitions * in `source` and `dest` properties of firewall rules Standard IP alias `local_network` ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This alias is automatically defined. Please use the following command to see assigned values: ---- # pve-firewall localnet local hostname: example local IP address: 192.168.2.100 network auto detect: 192.168.0.0/20 using detected local_network: 192.168.0.0/20 ---- The firewall automatically sets up rules to allow everything needed for cluster communication (corosync, API, SSH) using this alias. The user can overwrite these values in the cluster.fw alias section. If you use a single host on a public network, it is better to explicitly assign the local IP address ---- # /etc/pve/firewall/cluster.fw [ALIASES] local_network 1.2.3.4 # use the single ip address ---- IP Sets ~~~~~~~ IP sets can be used to define groups of networks and hosts. You can refer to them with `+name` in the firewall rules' `source` and `dest` properties. The following example allows HTTP traffic from the `management` IP set. IN HTTP(ACCEPT) -source +management Standard IP set `management` ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This IP set applies only to host firewalls (not VM firewalls). Those ips are allowed to do normal management tasks (PVE GUI, VNC, SPICE, SSH). The local cluster network is automatically added to this IP set (alias `cluster_network`), to enable inter-host cluster communication. (multicast,ssh,...) ---- # /etc/pve/firewall/cluster.fw [IPSET management] 192.168.2.10 192.168.2.10/24 ---- Standard IP set 'blacklist' ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Traffic from these ips is dropped by every host's and VM's firewall. ---- # /etc/pve/firewall/cluster.fw [IPSET blacklist] 77.240.159.182 213.87.123.0/24 ---- [[ipfilter-section]] Standard IP set 'ipfilter-net*' ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ These filters belong to a VM's network interface and are mainly used to prevent IP spoofing. If such a set exists for an interface then any outgoing traffic with a source IP not matching its interface's corresponding ipfilter set will be dropped. For containers with configured IP addresses these sets, if they exist (or are activated via the general `IP Filter` option in the VM's firewall's 'options' tab), implicitly contain the associated IP addresses. For both virtual machines and containers they also implicitly contain the standard MAC-derived IPv6 link-local address in order to allow the neighbor discovery protocol to work. ---- /etc/pve/firewall/.fw [IPSET ipfilter-net0] # only allow specified IPs on net0 192.168.2.10 ---- Services and Commands ~~~~~~~~~~~~~~~~~~~~~ The firewall runs two service daemons on each node: * pvefw-logger: NFLOG daemon (ulogd replacement). * pve-firewall: updates iptables rules There is also a CLI command named 'pve-firewall', which can be used to start and stop the firewall service: # pve-firewall start # pve-firewall stop To get the status use: # pve-firewall status The above command reads and compiles all firewall rules, so you will see warnings if your firewall configuration contains any errors. If you want to see the generated iptables rules you can use: # iptables-save Tips and Tricks ~~~~~~~~~~~~~~~ How to allow FTP ^^^^^^^^^^^^^^^^ FTP is an old style protocol which uses port 21 and several other dynamic ports. So you need a rule to accept port 21. In addition, you need to load the 'ip_conntrack_ftp' module. So please run: modprobe ip_conntrack_ftp and add `ip_conntrack_ftp` to '/etc/modules' (so that it works after a reboot) . Suricata IPS integration ^^^^^^^^^^^^^^^^^^^^^^^^ If you want to use the http://suricata-ids.org/[Suricata IPS] (Intrusion Prevention System), it's possible. Packets will be forwarded to the IPS only after the firewall ACCEPTed them. Rejected/Dropped firewall packets don't go to the IPS. Install suricata on proxmox host: ---- # apt-get install suricata # modprobe nfnetlink_queue ---- Don't forget to add `nfnetlink_queue` to '/etc/modules' for next reboot. Then, enable IPS for a specific VM with: ---- # /etc/pve/firewall/.fw [OPTIONS] ips: 1 ips_queues: 0 ---- `ips_queues` will bind a specific cpu queue for this VM. Available queues are defined in ---- # /etc/default/suricata NFQUEUE=0 ---- ifdef::manvolnum[] include::copyright.adoc[] endif::manvolnum[] Notes on IPv6 ^^^^^^^^^^^^^ The firewall contains a few IPv6 specific options. One thing to note is that IPv6 does not use the ARP protocol anymore, and instead uses NDP (Neighbor Discovery Protocol) which works on IP level and thus needs IP addresses to succeed. For this purpose link-local addresses derived from the interface's MAC address are used. By default the 'NDP' option is enabled on both host and VM level to allow neighbor discovery (NDP) packets to be sent and received. Beside neighbor discovery NDP is also used for a couple of other things, like autoconfiguration and advertising routers. By default VMs are allowed to send out router solicitation messages (to query for a router), and to receive router advetisement packets. This allows them to use stateless auto configuration. On the other hand VMs cannot advertise themselves as routers unless the 'Allow Router Advertisement' (`radv: 1`) option is set. As for the link local addresses required for NDP, there's also an 'IP Filter' (`ipfilter: 1`) option which can be enabled which has the same effect as adding an `ipfilter-net*` ipset for each of the VM's network interfaces containing the corresponding link local addresses. (See the <> section for details.) Avoiding link-local addresses on tap and veth devices ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ With IPv6 enabled by default every interface gets a MAC-derived link local address. However, most devices on a typical {pve} setup are connected to a bridge and so the bridge is the only interface which really needs one. To disable a link local address on an interface you can set the interface's `disable_ipv6` sysconf variable. Despite the name, this does not prevent IPv6 traffic from passing through the interface when routing or bridging, so the only noticeable effect will be the removal of the link local address. The easiest method of achieving this setting for all newly started VMs is to set it for the `default` interface configuration and enabling it explicitly on the interfaces which need it. This is also the case for other settings such as `forwarding`, `accept_ra` or `autoconf`. Here's a possible setup: ---- # /etc/sysconf.d/90-ipv6.conf net.ipv6.conf.default.forwarding = 0 net.ipv6.conf.default.proxy_ndp = 0 net.ipv6.conf.default.autoconf = 0 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.default.accept_ra = 0 net.ipv6.conf.lo.disable_ipv6 = 0 ---- ---- # /etc/network/interfaces (...) iface vmbr0 inet6 static address fc00::31 netmask 16 gateway fc00::1 accept_ra 0 pre-up echo 0 > /proc/sys/net/ipv6/conf/$IFACE/disable_ipv6 (...) ----