Application Gateways

Application Gateways
A Very Brief Introduction

Prof. David Bernstein
James Madison University

Computer Science Department

bernstdh@jmu.edu

Filters

Traditional:
- Each datagram is examined in isolation; some are allowed to pass and others aren't
Stateful:
- Track TCP connections and use state information to determine which datagrams can and can't pass

Filters (cont.)

An Observation:
- Filtering is done based on IP addresses and ports
Shortcomings:
- We sometimes want to restrict access based on identity (e.g., username)

Application Gateways

Defined:
- An application-specific server through which inbound and outbound data must pass
Problems:
- Reduced performance
- One gateway per application