Reflections On Host Firewalls

The information below is for an old version of the document
Document Type Expired Internet-Draft (iab IETF)
Author Dave Thaler 
Last updated 2013-12-23 (latest revision 2013-06-21)
Replaces draft-thaler-iab-host-firewalls
Stream IAB
Intended RFC status (None)
Expired & archived
pdf htmlized (tools) htmlized bibtex
Additional Resources
Stream IAB state Active IAB Document
Consensus Boilerplate Unknown
RFC Editor Note (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


In today's Internet, the need for firewalls is generally accepted in the industry and indeed firewalls are widely deployed in practice. Often the result is that software may be running and potentially consuming resources, but then communication is blocked by a firewall. It's taken for granted that this end state is either desirable or the best that can be achieved in practice, rather than (for example) an end state where the relevant software is not running or is running in a way that would not result in unwanted communication. In this document, we explore the issues behind these assumptions and provide suggestions on improving the architecture going forward.


Dave Thaler (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)