Hosts

Hosts is a passive inventory of every address GridNMS has actually seen on your network — not just the devices you’ve deliberately added. It’s built automatically from information your monitored routers and switches already have: their ARP tables, which map an IP address to a MAC address and the switch port it was seen on.

Nothing on this page is probed or scanned. If it shows up here, it’s because one of your monitored devices reported seeing it — so the list only ever reflects what your existing network gear already knows.

Where to find it

Open Explore → Hosts.

The host list

Each row is one address GridNMS has learned about:

Column	Description
MAC Address	The hardware address of the host.
Vendor	The hardware manufacturer, looked up from the MAC address.
IP	The IP address it was seen using.
Hostname	The name it resolved to, when known.
Device	The managed device whose ARP table this host was learned from — click through to that device.
Interface	The port on that device the host was seen on.
VLAN	Which VLAN the host was on, if known.
First Seen / Last Seen	When GridNMS first and most recently saw this host.

Use the search box to filter by MAC, IP, hostname, device name, or interface. Narrow further with the device picker or the VLAN filter.

Host detail

Click any row to open a detail view for that host:

• Current Location — its IP, hostname, vendor, the managed device and interface it was last seen on, its VLAN, and when it was first and last seen.
• Services — any open ports GridNMS has found on this host’s IP address from a network discovery scan. This section stays empty until a scan has actually reached the host — it’s not a claim that the host has no open ports, only that none have been found yet.
• Movement History — a log of every device, interface, and VLAN this host has been seen on over time, most recent first. This is what tells you a laptop moved from one switch port to another, or that an IP was reassigned to a different MAC address.

How a host differs from a managed device

A host is something GridNMS has merely observed — an address your network gear has reported seeing, with no monitoring performed on it directly. A managed device (see Devices & Inventory) is something you’ve explicitly added, with credentials GridNMS actively polls on a schedule, and which can raise its own events.

The two aren’t mutually exclusive. If a host’s IP or MAC address matches one of your managed devices, its detail view shows a “This node is a managed device” banner linking straight to that device — the same physical machine, seen from two angles.

The Hosts page itself doesn’t offer a way to promote a host into a managed device. If the host also shows open ports under Services, the Applications page can add it as a managed device — along with monitors for whatever it’s running — in a couple of clicks. Otherwise, add it manually under Devices & Inventory using the same IP address.

Where to go next

• Turn a host with discovered services into a managed device from Applications.
• Manage your monitored inventory in Devices & Inventory.
• Find new devices proactively with Network Discovery.
• See how a host’s device connects to the rest of the network in Graph Explorer.