Troubleshoot Connections With DPS' Free Network Utility app

As you familiarize yourself with new protocols and devices, trying to diagnose issues or network connections can be a bit confusing at the device level. In response to many tech support requests, we decided to build this free network utility application to you (and our own engineers) troubleshoot the most common issues our clients face, as well as give you some useful network statistics.

Typically, network tools try to be way too smart and end up losing a lot of functionality. Instead, we built this tool to provide you with as much control as possible when troubleshooting, so you can ensure your devices work correctly.

Features

• Create and send
  • UDP/TCP packets
  • SNMP GET, SET, and Trap messages
  • DCPx Polls
  • Ping and Traceroute
• Respond to
  • UDP/TCP packets
  • SNMP GET, SET, and Trap messages

Installation

• For Windows
• Mac
• Windows-Portable

Supported Platforms

• 32/64 bit
  • Windows 7 or newer
  • Windows Server 2008 or newer
  • Ubuntu 12.04 or newer
• 64 bit only
  • macOS 10.10 (Yosemite) or newer

General configuration

Each tab listens for a specific protocol on its own port. Any available port can be used but some protocols have a standard value.

• SNMP Get/Set - 161
• SNMP Traps - 162
• DCP - 2001

Ping/Traceroute uses ICMP and does not require you to set a port. If a port is in use already, a random port will be used instead. Setting the port to 0 will always choose a random port.

Sending messages

The message builder layout will change depending on the protocol type selected. The interval (in milliseconds) and repetition fields allow for repeatedly sending the same message at a regular interval. Repeated messages can be stopped by clicking the X next to the target IP in the bottom left corner of the application.

You can also save a message to send later.

Setting up responses

Automatic replies can be set up for incoming UDP/TCP packets and SNMP requests. UDP/TCP packets can be matched directly from their contents or by a regular expression. SNMP responses are matched by the request OID or optionally a previous OID value for get-next requests.

Saving logs

All traffic logs can be exported to a comma or space delimited log file. The default save location is in the logs folder but can be changed when saving.

UDP/TCP

Send a message over UDP/TCP

Similar to a tool like Packet Sender, the app lets you test sending TCP and UDP packets. The content of the message can be entered as an ASCII string or space separated hex values. If the protocol is TCP, the connection will be closed after sending a message unless "Keep TCP connection" is checked. With it checked, you'll be able to continue sending messages over the same connection.

Set up a UDP/TCP response

Active responses are matched against incoming packets. If there are multiple responses set up, the first one that matches will be used. Packets can be matched based on:

• ASCII content
• Hex content
• Regular expression

ASCII and hex matches are a simple case insensitive comparison between the raw TCP/UDP data and the match string. Regex comparisons will be run against the ASCII content with the global and case insensitive flags on. Capture groups in the match string can be used in the response if the response type is regex as well.

SNMP

SNMP troubleshooting with the Network Utility App can save you a ton of time versus trying to use your RTU to test SNMP requests. Using this tool, you can quickly simulate SNMP messages as a manager or agent. Simply fill out the appropriate fields to test your desired functionality.

SNMP GET/SET requests

SNMP GET/SET request fields

• OID - Object Identifier. This identifies the value to make a request for.
• Community - The community string for community based authentication (v1, v2c). This needs to match the community of the target device or the request will be ignored.
• Version
  • v1 - Set if the receiving device does not support later versions.
  • v2c - Set if the receiving device does not support SNMPv1.
  • v3 - Adds user based authentication and encryption of SNMP data.
• Operation
  • GET - Retrieve the value of the OID.
  • SET - Set the value of the OID on your target device.
  • GET-NEXT - retrieve the value of the next OID in the MIB.
  • GET-BULK - multiple get-next requests to be returned in the same packet.
• Port - The standard port for SNMP requests is 161.
• Timeout - How long to wait for a response before retrying.
• Retries - The number of times to retry the request if no response is received. If interval and repetitions are set, the request will be repeated even if the previous attempt is still ongoing.

Keep in mind, the value and data type must be specified for SET requests.

SNMP Traps

SNMP Trap fields

• Community - the community string for community based authentication (v1, v2c). This needs to match the community of the target device or the trap will be ignored.
• Port - the standard port for SNMP traps is 162.
• Version
  • SNMPv1 traps have additional data fields and use a different PDU format from other SNMP messages.
  • SNMPv2c uses the standard SNMP PDU with the timestamp and trap OID as the first 2 varbinds.
  • v1
    • Enterprise - OID that indicates what the device sending the trap is.
    • Source Address - The address of device sending the trap.
    • Specific Trap - A specific trap value.
    • Generic Trap - Indicates if the trap is a preset type or vendor specific.
    • Timestamp - The system up-time.
  • v2c
    • Trap OID - Trap identification, for vendor specific traps this consists of the Enterprise and Specific trap values from a v1 trap.
    • Timestamp - the system up-time.
  • Varbinds
    • Additional data can be attached to the trap here. A varbind consists of an OID/Value combination.

SNMP response

• Community - Community string of the agent.
• Version - SNMP version to use for the response.
• Read Only - Should the field be read only for SET requests.

DCP

DCP is the protocol used by DPS' T/Mon Master Station to poll a DPS NetGuardian. It is not a very popular protocol, but it is a very lightweight protocol which allows rapid polling of RTUs in the field, while consuming a very low amount of bandwidth. DCP troubleshooting can be tough if you've never experienced it, especially because there are not many tools or examples online that explain it. With DPS Network Utility, you will be able to simulate DCP polling from a T/Mon to a NetGuardian.

DCP fields

• Unit ID - The DCP unit ID set on the device, most devices will use unit ID 1.
• Operations
  • FUDR - Requests the state of all displays.
  • UPDR - Requests the state of displays that have changed.
  • DACK - Acknowledges the state changes from a UPDR poll.
• Port - The standard port for DCP is 2001 but can be changed on the device.
• Protocol - The standard transport for DCP is UDP but can be changed to TCP on the device.

Ping and Traceroute

Ping fields

• Address - Can be a url or IP.
• Timeout - How long to wait for a ping response, default 4000.
• Repetitions - Number of times to ping.
• Interval - Time in milliseconds between pings.

Traceroute fields

• Address - Can be a url or IP.