04 June 2009

Symptom:

One user of TNT Monitoring reported that his hardware firewall reported an out-of-licenses issue and blocked some Internet access after installing TNT Monitoring. In his case, this affected a Watchguard firewall, but Sonicwall firewalls and other models may have the same issue.

This symptom will only occur if installing TNT Monitoring on every workstation. This is not a recommended configuration.

Cause:

Many firewall devices targeted at small to medium sized businesses are licensed only for a specific number of users. This licensing is enforced by counting the number of IP addresses that establish outbound connections. The firewall may not necessarily always be aware of all users on the network, if they do not regularly establish outbound connections. As a result, such a firewall may well be used with users in excess of the purchased licenses.

TNT Monitoring establishes HTTPS connections every few minutes, usually to a monitoring server outside the local network. This will cause the firewall to “see” each computer, and accurately count the license usage.

Solution:

Purchase a licensing upgrade for the firewall for the proper number of users.