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Blocking Ports
User Guide
189
By default, the Firebox blocks several destination ports.
This measure provides convenient defaults which do not
normally require changing. Typically, the following ser-
vices should be blocked:
X Window System (ports 6000-6063)
The X Window System (or X-Windows) has several
distinct security problems that make it a liability on
the Internet. Although several authentication
schemes are available at the X server level, the most
common ones are easily defeated by a
knowledgeable attacker. If an attacker can connect
to an X server, he or she can easily record all
keystrokes typed at the workstation, collecting
passwords and other sensitive information. Worse,
such intrusions can be difficult or impossible to
detect by all but the most knowledgeable users.
The first X Window server is always on port 6000.
If you have an X server with multiple displays,
each new display uses an additional port number
after 6000, up to 6063 for a maximum of 64 displays
on a given host.
X Font Server (port 7100)
Many versions of X-Windows support font servers.
Font servers are complex programs that run as the
super-user on some hosts. As such, it is best to
explicitly disable access to X font servers.
NFS (port 2049)
NFS (Network File System) is a popular TCP/IP
service for providing shared file systems over a
network. However, current versions have serious
authentication and security problems which make
providing NFS service over the Internet very
dangerous.
N
OTE
Port 2049 is not assigned to NFS; however, in practice, this
is the most common port used for NFS. The port assigned for
NFS is assigned by the portmapper. If you’re using NFS, it
Summary of Contents for Firebox X10E
Page 1: ...WatchGuard Firebox System User Guide WatchGuard Firebox System ...
Page 12: ...xii WatchGuard Firebox System ...
Page 44: ...Chapter 2 Service and Support 22 WatchGuard Firebox System ...
Page 61: ...Cabling the Firebox User Guide 39 ...
Page 68: ...Chapter 3 Getting Started 46 WatchGuard Firebox System ...
Page 78: ...Chapter 4 Firebox Basics 56 WatchGuard Firebox System ...
Page 156: ...Chapter 8 Configuring Filtered Services 134 WatchGuard Firebox System ...
Page 182: ...Chapter 9 Configuring Proxied Services 160 WatchGuard Firebox System ...
Page 220: ...Chapter 11 Intrusion Detection and Prevention 198 WatchGuard Firebox System ...
Page 242: ...Chapter 12 Setting Up Logging and Notification 220 WatchGuard Firebox System ...
Page 256: ...Chapter 13 Reviewing and Working with Log Files 234 WatchGuard Firebox System ...
Page 274: ...Chapter 14 Generating Reports of Network Activity 252 WatchGuard Firebox System ...