Documentation forNetwork Topology Mapper

Online help

About SNMP

NTM uses Simple Network Management Protocol (SNMP) to retrieve information about device interfaces, ARP cache, CDP data, and a variety of other statistics. SNMP queries (polls) devices for specific information, and NTM acts as an SNMP manager, polling SNMP agents installed on managed devices. The following requirement must be met for NTM to successfully poll devices:

  • The device must have SNMP enabled. To enable SNMP on your devices, see the manufacturer’s documentation for the device.
  • The device and NTM must share the same SNMPv2c community strings or SNMPv3 security access.
  • SNMP (UDP port 161) must not be blocked between the device and NTM.

If your device fails to respond to SNMP complete the following troubleshooting steps:

  • Check the device NTM credentials (SNMPv2c community string or SNMPv3 credentials) and ensure they are the same as the credentials used in NTM.
  • Run a test from the NTM Add Credential interface before running discovery.
  • Use a third party protocol analyzer to capture packets between NTM and the node to evaluate the issue.

The screen captures below show a successful NTM query.

SNMP Get Request

SNMP Get Response

About Subnets

An IP subnet is a logical division of a network into one or more smaller networks. This is accomplished by borrowing some of the host IP address space in a network and allocating a portion of that space to a subnet address. For example, the IP network 10.0.0.0 has 224 host IP addresses. By specifying some of the host bits as subnet bits and assigning a subnet address the 10.0.0.0 network can contain a 10.1.1.0 subnet with 28 host addresses. A subnet mask is used to specify which part of the host bits are used to identify a subnet.

The sub-netting of the 10.0.0.0 network to the 10.1.1.0 subnet is accomplished by adding the subnet mask shown below.

Subnet = 10.1.1.0

Subnet mask = 255.255.255.0

This subnet mask indicates that the first three octets of the IP address specify the subnet and only the last octet specifies host addresses. The range of usable hosts is 10.110.1.0 to 10.110.1.254 (with .0 host allowed).

Change the encryption password

  1. Select Edit -> Change maps Encryption Password.
  2. Enter the Old Password.
  3. Enter the New Password.
  4. Enter the New Password again in the Confirm Password field, and then click Save.

Ignore ICMP-only nodes

If you select Ignore nodes that only respond to ICMP (ping) you will eliminate nodes that do not respond to SNMP or WMI. When ICMP only nodes are discovered NTM can only discover that some device is responding at the IP address. No node details or connectivity can be discovered for ICMP only nodes.

We recommend you select the ignore ICMP only nodes option.

Run custom tools

If you want to run some other utility on the node, you can create a Custom Tool. A custom tool can run your utility and pass the node's IP address, hostname, or SNMPv2 community string as parameters.

The available parameters are ${IP}, ${HOSTNAME}, ${COMMUNITY}. Placing any of these strings into your command line passes the appropriate parameter to the utility.

Example: DameWare Mini Remote Control (MRC)

Let us set up a custom tool to establish DameWare remote control of a node on your NTM map. Assuming you already have the DameWare utility installed on your NTM server, here is how we create the appropriate custom tool.

  1. Right-click any node and then select Integration with Custom Tools > Add Custom Tools.
  2. Add a custom tool defined as follows: Name: DameWare MRC

    Executable Path: C:\Program Files\SolarWinds\DameWare Mini Remote Control 10.0\DWRCC.exe (by default)

    Command line arguments:

    dwrcc.exe -c: m:${IP} -u:myUsername -p:"my Password”

  3. To use DameWare Mini Remote Control, right-click any node on the map and then select Integration with Custom Tools > DameWare MRC

For more information on DameWare command line parameters see http://support.dameware.com/kb/article.aspx?ID=300002

Example: DameWare Remote Control (DRS)

Let us set up a custom tool to establish DameWare remote control of a node on your NTM map. Assuming you already have the DameWare utility installed on your NTM server, here is how we create the appropriate custom tool.

  1. Right-click any node and then select Integration with Custom Tools > Add Custom Tools.
  2. Add a custom tool defined as follows: Name: DameWare DRS

    Executable Path: C:\Program Files\SolarWinds\DameWare Remote Support 10.0\ (by default)

    Command line arguments: None

  3. To use DameWare Mini Remote Control, right-click any node on the map and then select Integration with Custom Tools > DameWare DRS

Example: OpenSSH

Let us set up a custom tool to establish an SSH connection to a node using the third-party utility OpenSSH. The usage of SSH is typically ssh.exe user@remotehost. Here is how we create that.

  1. Right-click any node and then select Integration with Custom Tools > Add Custom Tools.
  2. Add a custom tool defined as follows: Name: SSH

    Executable Path: C:\Program Files (x86)\OpenSSH\bin\ssh.exe

    Command line arguments: Administrator@${IP}

Now when you want to SSH to a node, you:

  • Right-click any node and then select Integration with Custom Tools > SSH.

What are Hops?

Hops specify the number of devices that must be transverse to reach a target IP device. A zero hops discovery discovers all devices responding to the discovery protocols on the specified subnet or seed device, as well as any networks and subnets directly connected to devices on the target subnet. We recommend using a zero hop discovery.

A one hop discovery discovers all of the devices specified in the above zero hop discovery and all networks, subnets, and devices directly connected to all devices on the edge of the zero hops discovery.

Depending on the complexity of your network, discovering past zero hops has the potential to discover several times the number of subnets and hundreds of times the number of total devices. Discovering two hops or more has the potential of discovering thousands of subnets and devices.

Any discovery using more than zero hops may have a large impact on discovery performance.

What are VMware Credentials?

NTM uses a VMware API to query data from VMware servers. The API requires a VMware account with at least read-only access to VMware. The data from the VMware API allows NTM to associate host VM servers and the guest virtual servers.

To gather complete information about the guest servers, ensure that the guest servers’ IP addresses and VMware credentials are included in your discovery.

What Permissions are required for VMware queries?

To query VMs from NTM you must use an account that has Administrator access on the target VMware server.

When not to use Bridge Tables

Bridge tables are used by NTM to discover connections and calculate connectivity. Selecting Don’t use Bridge Table information to calculate network topology eliminates the bridge table information from the connection calculations. Connectivity discovered using bridge table information may be less accurate then with Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP), however, it is still a valuable source of data. Additionally, eliminating bridge tables may decrease the time needed to calculate connectivity.

OIDs that NTM needs poll for bridge table information are these:

Q-BRIDGE-MIB:

dot1qTpFdbTable 1.3.6.1.2.1.17.7.1.2.2

For BRIDGE-MIB:

dot1dTpFdbTable 1.3.6.1.2.1.17.4.3

Bridge table information has a much greater impact on Orion Network Atlas maps; therefore, if you will be importing maps from NTM to Orion Network Atlas we recommend you do not use bridge table information.

Windows Credentials (WMI)

You must use a Windows administrator account to collect details about Microsoft Windows servers. We use a technology called WMI to retrieve this information and this information is only available if we can provide administrator credentials.

Information we can retrieve for Microsoft Windows servers using WMI includes:

  • IP Address
  • Node name
  • MS Software (Machine Type)
  • System Description
  • System Location
  • Contact

All of the above except Machine Type are discovered in SNMP discovery as well.

Frequently Asked Questions

What does "Requests made" mean in discovery?

Request made represents the sum of the SNMP, WMI, VMware and ICMP requests sent by the NTM discovery engine to all of the nodes. This number will increment through the discovery process and will be several times larger than the number of nodes discovered.

Why does my map show unidentified devices or unknown device types connected to one of my routers or switches?

NTM can determine that an unknown device is connected to a specific interface on a fully discovered device using the IP address of the discovered device’s interfaces and the IP address of the unknown device.

Why are some unknown devices shown with no connectivity?

Devices that only respond to ICMP and cannot be determined to be directly connected to a known device can only be shown as unknown devices. Use the Ignore nodes that only respond to ICMP (ping) discovery option to discover only connected devices.

What database does NTM use?

NTM uses Microsoft SQL server Compact v3.5 SP2. This database is installed in \Program Files\Microsoft SQL Server during NTM installation. This database is not accessible from outside the system on which NTM is installed.

What does the log adjuster tool do?

Log adjuster allows you to change the level of event logging for NTM. This may be required if you are troubleshooting an issue with SolarWinds Technical Support. Do not change the settings in this tool unless you are requested to do so by Technical Support.

What does the Create Tech diagnostic file tool do?

The diagnostics tool creates files for SolarWinds Technical Support. This may be required if you are troubleshooting an issue with SolarWinds Technical Support. Do not use this tool unless you are requested to do so by Technical Support.

What does the Grab SNMPWalk tool do?

The SNMPWalk tool begins with the specified Root OID and queries the device for each OID in sequence, displaying its current value.

What does the Discovery Log Utility do?

For any node discovery the Discovery Log records devices for which SNMP information could not be retrieved.

How long does it take to complete a discovery?

The length of discovery depends on several factors including:

  • The IP range or size of the network specified.
  • The number and type of nodes discovered.
  • The number of methods used in discovery (SNMP, ICMP, VMware API, WMI).
  • The number of discovery hops allowed.
  • The number of networks directly connected to discovered devices.

What can I do to speed up discovery?

Some options include:

  • Eliminate any discovery methods that do not apply to the network.
  • Use a specific IP Address Range rather than a seed device or a subnet.
  • Use a zero hop count discovery.

What do the Spanning Tree State numbers mean?

  • 1 = disabled o 2 = listening o 3 = learning o 4 = blocking
  • 5 = forwarding

NTM supports only Common Spanning Tree (CST) data; IEEE 802.1Q.

Which map layout option should I use?

The layout options are available to make it easier for you to use maps in a format that you prefer. You can use the layout that makes the best fit for your network and any existing maps you have.