Networks
The networks VMs are attached to. A network here is the engine's own construct: a VLAN, the addresses on it, and whatever mapping or routing takes traffic in and out of it.
A network that is up is carrying traffic; one that is down exists in the register but nothing is attached or routed. Names and allowed ports can be changed while a network is down.
Add network
Makes a network of the chosen type and, for the types that need one, takes an address from the engine's own ranges. A VM can also have one made for it as it is created, on the VMs tab.
Name
What the network is called. Left empty, the engine names it after its type and number.
Type
What kind of network this is, which decides how traffic reaches the VMs on it.
- IP mapping - the VM keeps a private address and the engine maps a public one onto it. The usual choice, and the one that lets a VM be reached from outside without handing it a public address.
- Private - reachable from other VMs on this engine and nowhere else.
- External IP - the VM holds a public address itself.
- Gateway (NAT) - outbound traffic only, translated through the engine.
- Remote IP - for an engine without public addresses of its own: a public
address at the registry's server, tunnelled to the
VM's private address here, for the ports allowed. Only on an engine that is
linked to the registry and has remote IPs switched on (
REMOTE_IP_ENABLED). The tunnel opens when the network is activated and closes when it is deactivated; removing the network gives the address back.
Allowed ports
Which ports a mapped or public address lets in, as a comma-separated list - 80,
443 for a web server. Empty allows none, which leaves the VMs reachable from
their own network and from the console but not from outside.
DNS
On an engine linked to the registry, a network with a public address has a name
in the engine's DNS zone, <address>.<engine ID prefix>.<zone>, and stacks on it
can register names of their own that point there. The network's details list
these names, and a VM's details list those of its networks. The zone itself is
managed at the registry, which the Manage … at the registry link opens. Once an
hour the engine removes the address names of addresses no network holds any
more.
VLAN
The VLAN this network is carried on. Left empty the engine takes the next free one; giving a number puts this network on an existing VLAN.
Status
What a network's status says is worked out from what the engine finds: whether its VLAN is there, whether the DHCP server hands out its address, and whether its external address is mapped.
Up
Active: its VLAN is up and it does its job - the DHCP server hands its VM its address, and its external address and ports are mapped where it has them.
NAT
Partly active: its VLAN is up, so the VMs on it reach the internet through the engine's NAT, but it is not serving its own address - the DHCP server does not hand it out, or its external address is not mapped. Activating it brings it up.
Down
Not active: its VLAN is not set up on this engine. Activating it brings it up.
New
Just created, and not activated yet.
On the way
Activating, deactivating, stopping or removing: the engine is bringing the network up, taking it down to NAT only, taking its VLAN down, or deleting it.
Traffic
How much a network has carried: the bytes its VMs received (in) and sent (out), as their nodes report them. The table shows the last 24 hours, with a line for its shape, an hour a point and the newest on the right; the details show the last hour, the last 24 hours and the month so far.
It is the VMs' traffic on all their network cards, so a VM on two networks counts in full on both. A network no VM has reported for shows a dash, which is not the same as nothing carried.
Activating a network
Brings the network up: the VLAN, the addresses, the firewall rules and the routing that go with its type. Deactivating takes all of that down again and leaves the network in the register, so it can be brought back up as it was.