TCP/UDP Check Basics

This article will cover the creation and purpose of TCP checks, Uptime.com functionality that monitors responses on a TCP port. The following tutorial assumes you are logged into Uptime.com.

TCP Check Basics

To add a new TCP check, click Monitoring followed by Checks and then Add New. Select TCP Port as your Check Type.

With a TCP check, you will know which servers are responsive and have a rapid notification if something goes down. Any business may work with contractors from all over the world who require access to sensitive parts of a website or system. A TCP check is an active monitoring system you can use to ensure that access remains constant and open.

This resource is particularly valuable to IT departments that manage web and internal infrastructure, as well as connectivity.

TCP Check: Ensure FTP is Available from Many Countries

This check helps ensure everyone on your team can access internal resources, such as FTP. It utilizes an advanced setting to customize how many servers can go down before you receive an alert.

Required information for the TCP check includes:

  • Check name
  • Domain name or IP address of the server to check
  • TCP port number to check (21 for the example below)
  • Defined probe server locations
  • A customized alert if three probe servers are non-responsive
  • Escalate the issue to IT Support if downtime is longer than 5 minutes

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The test queries to port 21 at one-minute intervals and sends an alert if access is denied from three separate locations throughout the world.

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A failed TCP check will escalate the problem to relevant contacts (your IT department) if the outage is longer than 5 minutes.

For a detailed breakdown of each Parameter, please visit the Field Explanation support article.

Failed Checks

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If a TCP check fails, the error message will show a failure, list locations that failed to receive a response, and technical details about the downtime.

UDP Check - Ping Available Messaging Platforms

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UDP is best suited for monitoring peer-to-peer sharing tools and applications requiring less packet accuracy. This is useful for IT departments to ping a particular VoIP service and ensure a line is always available for executive conferences or weekly team meetings.

Before you begin, you need to format a string or data to send, and a string to expect that your server will understand and that Uptime.com will recognize.

To add a UDP check, first click Monitoring, followed by Checks, then Add New. Select UDP as your check type.

A UDP check requires:

  • A domain name or IP address of the server to check
  • Port number
  • String to Send
  • String to Expect

The UDP check will not run without filling out these fields. Many of the Advanced and Escalation options available in TCP checks are available in UDP checks as well. One useful field for monitoring of UDP might be the Maintenance tab.

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Maintenance scheduling allows Uptime.com to ignore failed UDP checks for a specified period. Regular updates might pull the system offline and trigger an escalation for a failed UDP check. Executives that use this system would find it inconvenient to receive fail notifications at odd hours of the night. Also, remember to set your Sensitivity to two or more locations to avoid false positives.

Finalizing Your TCP/UDP Check

Before saving your TCP check, make sure the following fields are complete:

  • Name of the check
  • Defined check interval
  • Contacts that should be notified
  • Locations of probe servers
  • Select TCP or UDP check type
  • Enter the domain or IP address of the server
  • Port number
  • For UDP, enter String to Send and a String to Expect

Once the check has been created, and any proper escalations or maintenance windows set, no further input is necessary. We can edit the check at a later date to add a new server location, change when and how escalation occurs, or any other parameter as needed.

Optional Parameters

Though the following fields are optional, they have some useful properties that may apply to your particular uptime check. Please refer to the Field Explanation support article for a more comprehensive explanation of terms.

 

  • String to Send (TCP)
  • String to Expect (TCP)

 

In the UDP example, we looked at the value of a string to expect, to verify connectivity. For TCP, which provides a higher packet accuracy, developers may find these features useful when attempting to test for correct behavior, for example in APIs, or when monitoring sites or infrastructure in other ways.  

Advanced Options

Some advanced options provide helpful functionality to TCP/UDP checks that webmasters and IT teams may find valuable.

 

  • Sensitivity
  • Use IP Version
  • Include in Metrics
  • Notes

 

Remember to check the Field Explanation support article for more detailed definitions of these terms.