There are no known firewalls, anti-virus software, browser add-ons, etc. that block PubNub. PubNub communication occurs through TCP tunneling via HTTP requests and works even in the strictest antivirus environments. PubNub uses an adaptive transport mechanism that works exceptionally well when confronted with proxy authorities, firewalls and antivirus software such as Avast.
In case of any questions, please contact firstname.lastname@example.org.