We've noticed a number of times that, despite having created a custom firewall rule, that rule is not applied, and instead ESS pops-up a warning dialog box asking what to do. If we permanently allow the traffic via the warning dialog box (remember action or create custom rule), another, duplicate rule is created. Take a look at this ESS warning dialog box: Here's a rule that was created before we got the ESS warning: For some reason, the rule did not apply to allow the traffic. It should be noted that the rule does not restrict IP addresses (whereas the warning dialog box specifies an IP address), but we've had rules that are specific to the IP address displayed in the ESS warning dialog box, yet don't apply. Also note: the ESS warning dialog box shows protocol "TCP & UDP". When trying to create a rule using this dialog box (remember or custom), ESS pre-populates the rule with protocol "TCP" (# 6). Whether the rule is "TCP" or "TCP & UDP" -- we've even tried having 2 simultaneous rules, one for each -- the rule is not applied and an ESS warning dialog box pops-up. A couple observations: 1) this "rule not applying" situation usually occurs once, after rebooting; after a new (duplicate) rule is created it seems ESS does apply that new (duplicate) rule; if a new rule is not created, the warning dialog box continues to pop-up; after rebooting, even the new (duplicate) rule is not applied (with the exception noted in #2, below) 2) the application in question is on a drive (D: drive) that must be mounted after rebooting; this usually happens via Task Scheduler, but when it doesn't, we have to manually mount it; it appears (though not confirmed) that the "rule not applying" situation occurs when, after a reboot, the drive does not automatically mount Any thoughts on why an existing rule is effectively ignored? .