What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

Which servers does PRTG connect to for software auto-update, activation, etc.?



The system running our PRTG core server does not have full internet access. Which URLs do I need to make available to the PRTG core server so I can use the auto-update functionality and automatic software activation? Are there sensor types that connect to external sources?

activation auto-update domains email external images privacy prtg update-check urls

Created on Feb 21, 2012 10:30:34 AM by  Daniel Zobel [Product Manager]

Last change on Mar 9, 2022 2:27:25 PM by  Frank Hadasch [Paessler Support] (0) 1

4 Replies

Accepted Answer



This article applies as of PRTG 22

PRTG connections to external servers

PRTG needs to connect to several external servers for full functionality. These connections are required for several purposes, such as PRTG updates and licensing, for notifications, and for monitoring with certain sensor types.

See the table below for external servers that PRTG tries to reach, depending on your PRTG usage.


To use auto-update, the PRTG core server system needs internet access (either directly or via proxy) to different (sub)domains so that update checks and downloads can work correctly:

autoupdate.paessler.comhttps443Hosted on Cloudflare
updatecheck.paessler.comhttps443Hosted on Cloudflare
downloads.paessler.comHosted on Cloudflare

Note: Because the other IP addresses can change dynamically, we do not recommend that you apply policies based on them. We cannot provide IP addresses for Amazon servers. Here you can find information of Cloudflare IP ranges.

License activation

Software activation is a one-time process that is necessary for all installations that run with a license key. PRTG tries to automatically activate every installation on first startup. Afterward, it periodically connects at least every 7 days and receives updates on the license, for example, the remaining maintenance days.

For all of this to work, the PRTG core server system needs internet access (either directly or via proxy) to at least one of the following (sub)domains:

Important: We are currently (Q4, 2022) updating our backend infrastructure. This affects the (sub)domains below. After the update of each sub(domains) is finished, the IP address is no longer valid. All (sub)domains will be resolved to Cloudflare’s current IP ranges.

activation.paessler.comhttps443Hosted on Cloudflare
activation1.paessler.comhttps443Hosted on Cloudflare
(deprecation planned for 2023)
(deprecation planned for 2023

Important: The following information only apply to the activation of Paessler PRTG Enterprise Monitor and as of PRTG 21.4.73.

(Sub)domainProtocolPort #Remarks
services.paessler.comhttps443IP addresses:
• 2606:4700::6810:cd1e
• 2606:4700::6810:cc1e

Note: Because the IP addresses can change dynamically, we do not recommend that you apply policies based on them.

HTML emails

When you receive emails from PRTG that are created via the default HTML email templates, your email client may try to connect to the Paessler server to download images (for example, sensor icons). To be able to view these emails properly, allow your email client to get the images from our server.


Emails from Paessler directly come from mailserver.paessler.com with the IP address


Several sensor types need to connect to external servers to show monitoring data. Make sure that the probe system(s) on which you run such sensors can reach the target domains.

External sourceSensors and remarks
*.amazonaws.comAmazon CloudWatch sensors: The first part of the domain depends on your region and configuration.
https://api.prtgcloud.com:443Cloud HTTP v2 and Cloud Ping v2 sensors
http://windowsupdate.microsoft.com and other Windows update domainsWindows Updates Status (PowerShell) sensor (if WSUS is not available)
Automatic Root Certificates Updates (via Akamai CDN)SSL-secured sensor connections (see Why is there strange traffic on a probe when monitoring ESX hosts?)
DNS serversDNS resolution for several sensor types (see How DNS query works on Microsoft TechNet)
https://manage.office.com/api/v1.0/Microsoft 365 Service Status sensor


External sourceNotification type
*.amazonaws.comAmazon SNS notification: The first part of the domain depends on your region and configuration.
https://api.prtgcloud.com:443Push notification

SMS notifications

See this article for the URLs that PRTG uses for the preconfigured SMS providers:

Geo Maps

See this article for the URLs that PRTG uses for the geographical maps providers:

Support bundles

You can send support requests and support bundles via the Contact Support form in PRTG. PRTG will securely transmit these requests to Paessler via the PRTG Cloud. Make sure that your PRTG core server has access to the internet and can reach the following URLs:



activation1.paessler.comhttps443Login page RSS Feed
www.paessler.comhttps443Login page RSS Feed


Created on Feb 21, 2012 11:16:01 AM by  Daniel Zobel [Product Manager]

Last change on Feb 19, 2024 1:08:51 PM by  Jacqueline Conforti [Paessler Support]



Would it be possible to provide a range of IP addresses/subnets of the above-mentioned servers? Applying policy based on domain names and a subsequent resolution has a severe impact on our enterprise firewall performance.


Martin Klepac

Created on Mar 4, 2016 10:06:37 AM




It looks lake this FQDN is also used 3.base.maps.api.here.com


Created on Jul 27, 2018 8:58:50 AM



Hello JohanLysen,
thank you for your reply and input.

Please note that there's a dedicated article for the URL's used by Geo-Maps, please refer to:

Best Regards,
Luciano Lingnau [Paessler Support]

Created on Jul 27, 2018 12:13:32 PM by  Luciano Lingnau [Paessler]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.