IP Address Management (IPAM)#

IP Address Management (IPAM) -- managing IP networks, addresses, and network components -- is an essential element of your IT documentation.

Overview#

i-doit comes with all object types and categories needed to cover IPAM in the standard installation. These include:

• Layer 3 Net
• Layer 2 Net
• Supernet

We focus primarily on these categories:

• Host address
• Net (category folder)
• Network (category folder)

As active network components, i-doit provides object types such as Switch and Router, and as active end devices Server, Client, VoIP Phone, and many more.

LAN#

Before documenting individual IP addresses, hostnames, and MAC addresses, it is worthwhile to document the corresponding LANs (Local Area Networks). The Layer 3 Net object type is suitable for this purpose. The Net category contains the essential attributes for maintaining an IP network:

• Type (IPv4, IPv6; selection field)
• Net address (text field) with subnet mask or CIDR notation (text fields; mutually dependent)
• Default gateway (dropdown selection field for active components, e.g., router)
• Reverse DNS (text field)
• DNS server (object browser)
• DNS domain (multiple selection)
• Layer 2 net assignment (for VLANs; object relationship; multiple selection)

In this category, you can also check whether networks have already been documented whose address range overlaps with the one specified here.

Supernets#

Supernets, i.e., the aggregation of multiple subnets into one network, can be documented in the Supernet object type. When the address range is defined in the Net category of an object of this type, the associated subnets are automatically linked. A tabular summary is provided by the Supernet category.

IP Address with Hostname#

Documentation of individual IP addresses takes place in the Host address category, which can be assigned to any object type. Since it is a list category, any number of IP addresses per object can be specified. The category provides some automation features beyond pure data maintenance to support the user. First, you should specify which type (i.e., which IP version) is used. Then the previously created network should be specified along with the type of address assignment (e.g., static). i-doit then suggests the next free IP address, which can be accepted or changed. It is also important to specify the hostname. Under DNS domain, you can choose from the domains assigned to the network, so that corresponding FQDNs (Fully Qualified Domain Names) can be formed from hostnames and domains.

IP List#

A comprehensive overview of each network is provided by the IP list category, which is assigned to the Layer 3 Net object type. A tabular list contains all objects assigned to this network, along with IP address, hostname, and type of address assignment. The latter is displayed in color, with a legend to the right of the list explaining the color coding.

The list can also be extended with additional objects without using the Host address category. Assignments can also be removed. For "smaller" networks (< 1,000 IP addresses), free IP addresses are also displayed; otherwise, a notification appears.

To avoid (unintentional) address conflicts, i-doit indicates duplicate IP addresses next to the table.

An additional table summarizes important network information (number of assigned and free IP addresses, address range, etc.).

VLAN#

For each Virtual LAN (VLAN) to be maintained, you create an object of type Layer 2 Net in i-doit. The important part is the category of the same name, where the VLAN ID is stored. There you can also connect a physical network with a VLAN via the Layer 3 net assignment attribute. Specifying IP helper addresses is also possible.

To bind a VLAN to a (virtual/physical) port, the corresponding port of an active network component should have been created beforehand. Either the port can be assigned in the component's object (category Port or Logical Port) or in the Layer 2 Net object in the category Assigned Ports or Assigned Logical Ports.

DHCP#

IP addresses are assigned in a network (objects of type Layer 3 Net) in various ways. While servers often receive a static IP address, clients usually receive one assigned via DHCP. The DHCP server may assign IP addresses dynamically or by reservation. To document this, a network can be divided into different ranges. The DHCP category serves this purpose.

When assigning an IP to a network (category Host address), the choice of address assignment affects the automatic allocation of the next free IP address. Conversely, it is possible to define a new (reserved/unreserved) DHCP range in the assigned network by specifically setting the address assignment.

Net Zones#

Apart from CIDR, a subnet can be logically divided into multiple segments. This is useful when assigning IP addresses for specific tasks or for specific departments.

Each segment is created as an object of type Net Zone. The category folder of the same name is available there. In the subordinate category Options, a zone color can be selected. This color is used in the Net > IP List category. Furthermore, the sub-category Zones displays the address ranges of the assigned subnets of type Layer 3 Net.

The assignment of a zone to a subnet takes place in the Net > IP List category of a subnet: First, you select an IP address or a range of IP addresses. Then you assign the segment to these IP addresses via the New zone button. The IP addresses are marked in the color of the zone.

In the Host address category, the next free IP address is automatically suggested based on the selected net zone. The Domain attribute in the Net Zone > Options category additionally ensures that when new IP addresses are assigned in the Host address category, this domain is automatically preselected.

DNS and FQDNs#

If you want to maintain information about the Domain Name System (DNS) and/or Fully Qualified Domain Names (FQDNs) used, you can do so with i-doit. For each Layer 3 Net, any number of DNS servers (object relationship) and domains can be stored in the Net category. Deviating settings for DNS servers and domains used can be stored per object in the Host address category. If an object receives one or more hostnames (category Host address) and information about the domains used, one or more FQDNs are derived, which are displayed automatically. Domains can be inherited through the assignment to a network. Additionally, search domains can be specified.

Gateways#

Network components can act as gateways to route connections from one network to other networks (routing). Each network typically has a so-called default gateway, which is used when no explicit routing rule applies. Such a default gateway is defined in i-doit for a network: Either you select an object that acts as default gateway in the Net category of a Layer 3 Net object. It is important that this object already has an IP address assigned to this network. Or you set the Default gateway for the network attribute to yes within the object in the Host address category.

IPv4 versus IPv6#

Even though the adoption of IPv6 in many enterprise LANs can be estimated as rather low, i-doit provides the basic elements for documenting IPv6 networks. As with IPv4, networks are defined and IP addresses assigned. Only the address assignment differs (SLAAC, DHCPv6, etc.). Additionally, the scope (global, link-local, etc.) can be specified. Both attributes belong to the Host address category.

WLAN#

Documenting WLANs does not fundamentally differ from the options already described. An access point (AP) can be documented as an object of type Wireless Access Point. In the WiFi device category, SSIDs and encryption details, among other things, are maintained.

WAN#

To document external connections, the WAN Lines object type is suitable. WAN stands for Wide Area Network. Similar forms such as Metropolitan Area Network (MAN) or Global Area Network (GAN) are intended to be covered by WAN.

Details about upstream and downstream, assigned LANs and VLANs, and more can be stored in the WAN Lines category.

VPN#

For Virtual Private Networks (VPN), there is neither a dedicated object type nor a special category in the standard installation of i-doit. It is recommended to use the Layer 3 Net object type and assign a descriptive name in the Object title so that the object is recognizable as a VPN. If additional VPN-specific attributes are needed, a dedicated object type and a custom category can help.

Related Topics#

"Pure" IPAM documentation is usually not sufficient: There are many adjacent topics that play a more or less important role. We would like to briefly touch on some of them below.

MAC Addresses and Ports#

In addition to IP addresses, you often want to document the associated MAC addresses for a host. These are uniquely assigned to a network port. In i-doit, the Port category in the Network category folder is used for documentation. There, additional (physical) properties of the port are specified. Additionally, one or more IP addresses can be permanently assigned to a port. Since the Port category is a list category, any number of ports can be created per object.

A helpful feature here is the ability to specify how many ports should be created simultaneously. A naming scheme (eth0, eth1, eth2) can also be applied.

A connection to another (active/passive) network component is possible per port entry: In the Port Browser, you first preselect the object and then the corresponding port. This means the ports should already exist before they are connected to each other.

Virtual Ports#

Physical ports can be combined into logical ones. This technique is often called trunking or bonding. To document this, the Logical Ports category in the Network category folder is used.

Cabling#

In i-doit, a clear distinction can be made between the different layers of the TCP/IP reference model. The topics above cover layers 3 with IP and 4 (MAC). For the remaining layers, i-doit provides further documentation features, for example for layer 1, which addresses the physical medium.

To document cables and their connections to active and passive components, i-doit already includes numerous object types (Cable, Patch Panel, Cable Tray, Conduit, etc.). The Cabling category handles the connection of objects of these types. This category can, but does not have to be, actively maintained. When a connection between two components is documented via the Port (Network) category, this category is automatically filled in and an object of type Cable is created.

Network Listener and Port Binding#

Analogous to cabling, the upper layers of the TCP/IP reference model can also be documented in i-doit. Which application opens which TCP/UDP connections and which application accesses which ports on third-party systems can be recorded in the Network Connections category folder. Within the folder, there are the categories Listener (port is opened) and Connection (port on third-party system is used). It should be ensured beforehand that the required software installations are documented in i-doit.

Further Links#

• doIT BETTER: IP Address Management (IPAM), blog article on i-doit.com with video
• German-language demo for the above "doIT BETTER" topic (Credentials: admin/admin)