Red Hat ENTERPRISE LINUX AS 2.1 Installation Manual page 60

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users on the network can access. A properly configured firewall can greatly increase the security of
your system.
Figure 3–12 Firewall Configuration
Choose the appropriate security level for your system.
High
If you choose
that are not explicitly defined by you. By default, only the following connections are allowed:
• DNS replies
• DHCP — so any network interfaces that use DHCP can be properly configured
If you choose
• Active mode FTP (passive mode FTP, used by default in most clients, should still work)
• IRC DCC file transfers
• RealAudio™
• Remote X Window System clients
High , your system will not accept connections (other than the default settings)
, your firewall will not allow the following:
High
Chapter 3:Installing Red Hat Enterprise Linux AS