Firewall Problems

HydroCAD^® Stormwater Modeling - Since 1986

Firewall Problems

Background

Starting with version 10.2, HydroCAD uses a cloud-based license manager to control access to the software. This requires that HydroCAD be able to communicate with the license server each time you start and stop the program.

How it works

For most HydroCAD users, the license manager does not require any special computer or network setup. This is because most networks allow full access over ports 80 and 443, as used by the HydroCAD license manager. This means that HydroCAD can run over most networks and firewalls without any special setup.

What can go wrong?

In some environments, your firewall may restrict traffic on ports 80 and 443 based on the actual content of the communication. Although this "packet inspection" provides additional network protection, it can also block the custom traffic that HydroCAD sends over these ports, resulting in HydroCAD error 211.

How do I resolve error 211?

To resolve error 211 you must allow all traffic over ports 80 and 443. It is not sufficient for there ports to be open to normal HTTP and HTTPS traffic. They must be open to all traffic, otherwise an error 211 may occur.

How do I change the firewall setup?

Given the large number of firewalls in use, we are not able to provide guidance on specific systems. This is an issue that must be resolved by your IT or ISP. To assist their efforts, you can send them a link to this page along with the details of the specific error 211 your received. In some cases, the firewall may even be operated by your ISP.

What if I don't want to allow all traffic on these ports?

To retain maximum protection by the firewall, you can create a special rule that allows full traffic only from the HydroCAD application. This will ensure that other programs on your computer cannot exploit the open ports for unintended purposes.

What if I cannot change the firewall settings?

If the firewall settings are beyond your control, you can probably use a VPN to avoid the firewall restrictions. A VPN allows your traffic to go through a "tunnel" to a remote server, thus encrypting the information and preventing inspection by the firewall and/or ISP.

For further information

Also see the license manager FAQ's