Proxmox VE Firewall

Introduction

Note: Proxmox VE Firewall is introduced in Proxmox VE 3.x as technology preview (code is currently in git only, packages will be available mid of July).

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 helps to make 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.

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

Fore each zone, you can define firewall rules for incoming and/or outgoing traffic.

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, 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 rule for all nodes

VM firewall configuration is read from:

/etc/pve/firewall/<VMID>.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/<nodename>/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.

Firewall Rules

Any firewall rule consists of a direction ('IN' or 'OUT') and an action (ACCEPT, DENY, REJECT). Additional options can be used to refine rule matches. Here are some examples:

[RULES]

#TYPE ACTION [OPTIONS]
#TYPE MACRO(ACTION) [OPTIONS]

# -i      <INTERFACE>
# -source <SOURCE>
# -dest   <DEST>
# -p      <PROTOCOL>
# -dport  <DESTINATION_PORT>
# -sport  <SOURCE_PORT>

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

IP Aliases

IP Aliases allows you to associate IP addresses of Networks with a name. You can 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 set up rules to allow everything needed for cluster communication (corosync, API, SSH).

The user can overwrite this values in the cluster.fw alias section. If you use a single host on a public network, it is better to assign the local IP address

# --- example: /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 them with '+name' in 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'

Those hosts 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')

Standard IP set 'blacklist'

Traffic from those hosts is dropped.

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

Above command reads an 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

Video Tutorials

• tbd.