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Configuring Your Firewall (Classic Products released after 1/1/2018) - OST QB DPC

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Every On Center Software Classic product requires communication via the Internet to activate licenses.  Clients must configure their networks appropriately or activation will fail.  Communication is initiated from the client software (OST, QB, ELM, etc.) to the Internet resource via the TCP protocol.  Our servers never initiate communications from the Internet resource into the clients internal network.

It is not possible to license Classic products without an Internet connection.

The services provided by these Internet resources include:

  • Local Software License Activation and Validation
  • Networked Software License Activation and Validation
  • Product Support Information (Software Updates)
  • Quick Bid e-Quotes, Supplier Lists, Partner databases and assemblies
  • On-Screen Takeoff Project Express and Takeoff Boost™

Access to these Internet resources may require you to modify your network (including software and hardware) firewall.  Our solutions are built for enterprise systems by only requiring outbound TCP access (the firewall handles the incoming response).  This minimizes security risks and should meet most IT security requirements.

On Center does not provide specific instructions on how to set up or modify firewalls because there is a multitude of firewall solutions on the market and each is set up differently.  On Center provides the following information so that clients can configure their own firewall solutions or to forward to a qualified IT professional for implementation.

The tables below include all the firewall configuration information required to run On Center Software solutions.

Domains (Recommended)

Do not configure firewalls to a specific IP address, use the DNS Name only.

DNS Name Port Numbers
*.flexnetoperations.com 8888, 443
*.oncenter.com 80, 443
*.constructconnect.com 80, 443
*.aptrinsic.com 80, 443 


If you are unable to whitelist the entire domains listed above, you'll need to add the individual entries below.

Do not configure firewalls to a specific IP address, use the DNS Name only.

DNS Name Port Numbers Purpose
oncenter.flexnetoperations.com 8888 *
Activating License Key
Activating Server Code
as1.oncenter.com 80 Checking for Updates
inapp.oncenter.com 80  Checking maintenance subscription status
mercury.oncenter.com  80  Checking registration information 
api.autonaming.ocs.constructconnect.com (v. and above) 443 Auto-Naming 
api-dot-smooth-grid-186620.appspot.com (v. and below) 443  Auto-Naming 
ocs-ml-sessions-prod (v. and below) 443  Auto-Naming 
www.oncenter.com 80 Support, Feature Requests, User Guides
equotes.oncenter.com 80 Sending eQuotes (receipt is handled through e-mail)
pe.oncenter.com 443 Sending/Receiving projects through Project Express
 *.aptrinsic.com80 Sending analytics to ConstructConnect about license, product, and feature usage (anonymous)

Port Forwarding
You must enable "port forwarding" for "TCP" in your router(s) for Port 8888. On Center cannot give you specific instructions for adding an entry to your router because each router's configuration process is different.  This gives you an idea of what you need to enter. If your company employs a "NAT" based router (Network Address Translation) it may be necessary to allow both outgoing and incoming communication to/from the workstations over port 80.


The following executables must be added as exceptions to local and network firewalls:

On-Screen Takeoff® and Digital Production Control™

ost.exe (installed to C:\Program Files (or Program Files (x86) on 64 bit machines)\On-Screen Takeoff 3\

Quick Bid®

quickbid.exe (installed to C:\Program Files (or Program Files (x86) on 64 bit machines)\Quick Bid 4\

Multiple Firewall Locations

Some organizations employ several layers of firewalls that can potentially block communication to or from a workstation or the server on which Enterprise License Server is installed, preventing licensing or features to work.  The list below is not all-inclusive but should give you an idea of where to check for firewalls that could be causing issues:

  • Windows Server OS Firewall
  • Windows Client Desktop Firewall
  • Virtual Server OS Firewall
  • 3rd Party Firewall/Filters Applications local to the Server
  • 3rd Party Firewall/Filters Applications local to the Client
  • Any Physical Hardware based Network Appliances/VPN/DMZ or Network Filters that can permit/refuse traffic or add latency to the connection

You must ensure that your company's are configured to allow the TCP traffic as described in this FAQ.  For assistance with configuring your firewalls and network appliances, please contact the vendor of your particular firewall product.  On Center Software is unable to assist with installing or configuring products we do not manufacture or sell.

Product documentation (user guides) describes functionality in the latest version of each major release and may not match the functionality in the version you are using. Please check the Product Information and Downloads pages by clicking one of the product buttons above.

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