3 include::attributes.txt[]
5 {pve} uses a bridged networking model. Each host can have up to 4094
6 bridges. Bridges are like physical network switches implemented in
7 software. All VMs can share a single bridge, as if
8 virtual network cables from each guest were all plugged into the same
9 switch. But you can also create multiple bridges to separate network
12 For connecting VMs to the outside world, bridges are attached to
13 physical network cards. For further flexibility, you can configure
14 VLANs (IEEE 802.1q) and network bonding, also known as "link
15 aggregation". That way it is possible to build complex and flexible
18 Debian traditionally uses the `ifup` and `ifdown` commands to
19 configure the network. The file `/etc/network/interfaces` contains the
20 whole network setup. Please refer to to manual page (`man interfaces`)
21 for a complete format description.
23 NOTE: {pve} does not write changes directly to
24 `/etc/network/interfaces`. Instead, we write into a temporary file
25 called `/etc/network/interfaces.new`, and commit those changes when
28 It is worth mentioning that you can directly edit the configuration
29 file. All {pve} tools tries hard to keep such direct user
30 modifications. Using the GUI is still preferable, because it
31 protect you from errors.
37 We currently use the following naming conventions for device names:
39 * Ethernet devices: eth[N], where 0 ≤ N (`eth0`, `eth1`, ...)
41 * Bridge names: vmbr[N], where 0 ≤ N ≤ 4094 (`vmbr0` - `vmbr4094`)
43 * Bonds: bond[N], where 0 ≤ N (`bond0`, `bond1`, ...)
45 * VLANs: Simply add the VLAN number to the device name,
46 separated by a period (`eth0.50`, `bond1.30`)
48 This makes it easier to debug networks problems, because the device
49 names implies the device type.
51 Default Configuration using a Bridge
52 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
54 The installation program creates a single bridge named `vmbr0`, which
55 is connected to the first ethernet card `eth0`. The corresponding
56 configuration in `/etc/network/interfaces` looks like this:
60 iface lo inet loopback
62 iface eth0 inet manual
65 iface vmbr0 inet static
74 Virtual machines behave as if they were directly connected to the
75 physical network. The network, in turn, sees each virtual machine as
76 having its own MAC, even though there is only one network cable
77 connecting all of these VMs to the network.
83 Most hosting providers do not support the above setup. For security
84 reasons, they disable networking as soon as they detect multiple MAC
85 addresses on a single interface.
87 TIP: Some providers allows you to register additional MACs on there
88 management interface. This avoids the problem, but is clumsy to
89 configure because you need to register a MAC for each of your VMs.
91 You can avoid the problem by ``routing'' all traffic via a single
92 interface. This makes sure that all network packets use the same MAC
95 A common scenario is that you have a public IP (assume `192.168.10.2`
96 for this example), and an additional IP block for your VMs
97 (`10.10.10.1/255.255.255.0`). We recommend the following setup for such
102 iface lo inet loopback
105 iface eth0 inet static
107 netmask 255.255.255.0
109 post-up echo 1 > /proc/sys/net/ipv4/conf/eth0/proxy_arp
113 iface vmbr0 inet static
115 netmask 255.255.255.0
122 Masquerading (NAT) with `iptables`
123 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
125 In some cases you may want to use private IPs behind your Proxmox
126 host's true IP, and masquerade the traffic using NAT:
130 iface lo inet loopback
134 iface eth0 inet static
136 netmask 255.255.255.0
141 iface vmbr0 inet static
143 netmask 255.255.255.0
148 post-up echo 1 > /proc/sys/net/ipv4/ip_forward
149 post-up iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
150 post-down iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
157 Bonding (also called NIC teaming or Link Aggregation) is a technique
158 for binding multiple NIC's to a single network device. It is possible
159 to achieve different goals, like make the network fault-tolerant,
160 increase the performance or both together.
162 High-speed hardware like Fibre Channel and the associated switching
163 hardware can be quite expensive. By doing link aggregation, two NICs
164 can appear as one logical interface, resulting in double speed. This
165 is a native Linux kernel feature that is supported by most
166 switches. If your nodes have multiple Ethernet ports, you can
167 distribute your points of failure by running network cables to
168 different switches and the bonded connection will failover to one
169 cable or the other in case of network trouble.
171 Aggregated links can improve live-migration delays and improve the
172 speed of replication of data between Proxmox VE Cluster nodes.
174 There are 7 modes for bonding:
176 * *Round-robin (balance-rr):* Transmit network packets in sequential
177 order from the first available network interface (NIC) slave through
178 the last. This mode provides load balancing and fault tolerance.
180 * *Active-backup (active-backup):* Only one NIC slave in the bond is
181 active. A different slave becomes active if, and only if, the active
182 slave fails. The single logical bonded interface's MAC address is
183 externally visible on only one NIC (port) to avoid distortion in the
184 network switch. This mode provides fault tolerance.
186 * *XOR (balance-xor):* Transmit network packets based on [(source MAC
187 address XOR'd with destination MAC address) modulo NIC slave
188 count]. This selects the same NIC slave for each destination MAC
189 address. This mode provides load balancing and fault tolerance.
191 * *Broadcast (broadcast):* Transmit network packets on all slave
192 network interfaces. This mode provides fault tolerance.
194 * *IEEE 802.3ad Dynamic link aggregation (802.3ad)(LACP):* Creates
195 aggregation groups that share the same speed and duplex
196 settings. Utilizes all slave network interfaces in the active
197 aggregator group according to the 802.3ad specification.
199 * *Adaptive transmit load balancing (balance-tlb):* Linux bonding
200 driver mode that does not require any special network-switch
201 support. The outgoing network packet traffic is distributed according
202 to the current load (computed relative to the speed) on each network
203 interface slave. Incoming traffic is received by one currently
204 designated slave network interface. If this receiving slave fails,
205 another slave takes over the MAC address of the failed receiving
208 * *Adaptive load balancing (balanceIEEE 802.3ad Dynamic link
209 aggregation (802.3ad)(LACP):-alb):* Includes balance-tlb plus receive
210 load balancing (rlb) for IPV4 traffic, and does not require any
211 special network switch support. The receive load balancing is achieved
212 by ARP negotiation. The bonding driver intercepts the ARP Replies sent
213 by the local system on their way out and overwrites the source
214 hardware address with the unique hardware address of one of the NIC
215 slaves in the single logical bonded interface such that different
216 network-peers use different MAC addresses for their network packet
219 For the most setups the active-backup are the best choice or if your
220 switch support LACP "IEEE 802.3ad" this mode should be preferred.
222 The following bond configuration can be used as distributed/shared
223 storage network. The benefit would be that you get more speed and the
224 network will be fault-tolerant.
226 .Example: Use bond with fixed IP address
229 iface lo inet loopback
231 iface eth1 inet manual
233 iface eth2 inet manual
236 iface bond0 inet static
239 netmask 255.255.255.0
242 bond_xmit_hash_policy layer2+3
245 iface vmbr0 inet static
247 netmask 255.255.255.0
256 Another possibility it to use the bond directly as bridge port.
257 This can be used to make the guest network fault-tolerant.
259 .Example: Use a bond as bridge port
262 iface lo inet loopback
264 iface eth1 inet manual
266 iface eth2 inet manual
269 iface bond0 inet maunal
273 bond_xmit_hash_policy layer2+3
276 iface vmbr0 inet static
278 netmask 255.255.255.0
287 TODO: explain IPv6 support?