Firewalls are a widely used security mechanism to provide access control and auditing at the border between "open" and private networks or administrative domains. As part of the network infrastructure they are strongly affected by the development and deployment of new communication paradigms and applications. Currently we experience a very fast rise in the use of multimedia applications. These differ in many aspects from "traditional applications", for example concerning bandwidth usage, dynamic protocol elements or multiple data flows for one application session. Corresponding firewall mechanisms and techniques did not change with the same dynamics though. Currently existing firewalls have problems supporting these new type of applications because to some extent they try to map the new characteristics to the manner of conventional applications which they are able to handle. We strongly believe that new application types require new firewall techniques and mechanisms. In this paper, we identify typical characteristics of multimedia applications that cause problems using traditional firewalls. Based on this analysis we deduce enhancements to existing firewalls that can be used to better adapt to a communication environment in which multimedia applications are used. We describe these enhancements in general, show a adequate systems architecture and present a implementation based on this design. The feasibility of that approach has been shown in the example scenario that we finally present.