User guide

Reference Guide 51
CHAPTER 5 Types of Services
This chapter describes well-known services, their protocols and ports as
well as special considerations for adding the service to a security policy
configuration. Rather than explain every service in detail, this chapter
explains the telnet service thoroughly as an example from which to
extrapolate configuration details for similar services. Services fall into two
broad categories–packet filters and proxies.
Packet Filter Services
Packet filter services examine the source and destination headers of each
packet. Packets are then either allowed or denied passage based on
whether the headers appear to be coming from and going to legitimate
addresses.
Any
The Any service should be used only to allow ALL traffic between any
two specific, trusted IP or network addresses. Configuring the Any
service opens a “hole” through the Firebox, allowing all traffic to flow
unfiltered between specific hosts. We strongly recommend that the Any
service be used only for traffic over a VPN.