firewall
Click on the red underlined text to get to the source
... cost of purchasing security hardware and software like firewalls
and one-time password generators), performance ...
... for each site to define classes of incidents and corresponding
responses. For example, sites with firewalls should set a threshold
on the number of attempts made to foil the firewall ...
... firewalls should set a threshold
on the number of attempts made to foil the firewall before triggering
a response? Escallation levels should be defined for both attacks
...
... a response? Escallation levels should be defined for both attacks
and responses. Sites without firewalls will have to determine if a
single attempt to connect to a host constitutes an incident? What
...
... unwilling or unable to provide similar protections internally. This
works fine as long as the outer defenses are never breached and the
internal users can be trusted. Once the outer shell (firewall) is
breached, subverting the internal network is trivial.
...
... active network interconnection
components that also includes components like firewalls, proxy-
servers, etc.
...
... networks) which are
accessible from the outside and another set which may be accessed
only within the site. Of course, there is usually a firewall which
connects these partitions. Great care must be taken to ensure that
...
... connects these partitions. Great care must be taken to ensure that
such a firewall is operating properly.
...
... Firewalls ...
... security measures in
use on the Internet is a "firewall." Firewalls have been given the
reputation of a general panacea for many, if not all, of the Internet ...
... use on the Internet is a "firewall." Firewalls have been given the
reputation of a general panacea for many, if not all, of the Internet
...
... Internet
security issues. They are not. Firewalls are just another tool in
the quest for system security ...
... at the network level. The level of security that a firewall provides
can vary as much as the level of security on a particular machine.
...
...
A firewall is any one of several mechanisms used to control and watch
access to and from a network for the purpose of protecting it. A
...
... access to and from a network for the purpose of protecting it. A
firewall acts as a gateway through which all traffic to and from the
...
... traffic to and from the
protected network and/or systems passes. Firewalls help to place
limitations on the amount and type of communication that takes place
between the protected network ...
... gateways"). The difficult part is establishing the criteria by
which the packets are allowed or denied access through the doors.
Books written on firewalls use different terminology to describe the
various forms of firewalls. This can be confusing to system
administrators ...
... Books written on firewalls use different terminology to describe the
various forms of firewalls. This can be confusing to system
administrators who are not familiar with firewalls. The thing to note
...
... various forms of firewalls. This can be confusing to system
administrators who are not familiar with firewalls. The thing to note
here is that there is no fixed terminology for the description of
firewalls ...
... firewalls. The thing to note
here is that there is no fixed terminology for the description of
firewalls.
...
...
Firewalls are not always, or even typically, a single machine.
Rather, firewalls are often a combination of routers ...
... Firewalls are not always, or even typically, a single machine.
Rather, firewalls are often a combination of routers, network
...
... host computers. Therefore, for the purposes of this
discussion, the term "firewall" can consist of more than one physical
device. Firewalls ...
... firewall" can consist of more than one physical
device. Firewalls are typically built using two different
components, filtering routers ...
... Filtering routers are the easiest component to conceptualize in a
firewall. A router moves data back and forth between two (or more)
different networks ...
... host
has to be protected very carefully. To make resources available to
legitimate users across this firewall, services have to be forwarded
by the bastion host ...
... etc.), proxy servers can be used to allow access to the resources
across the firewall in a secure way.
...
...
Firewalls are typically thought of as a way to keep intruders out,
but they are also often used as a way to let legitimate users into a
site. There are many examples where a valid ...
...
The current best effort in firewall techniques is found using a
combination of a pair of screening routers with one or more proxy
servers ...
...
Most firewalls provide logging which can be tuned to make security
administration of the network more convenient. Logging may be
...
... Commercial packages start at approximately $10,000US and go up to
over $250,000US. "Home grown" firewalls can be built for smaller
amounts of capital. It should be remembered that the correct setup
of a firewall ...
... firewalls can be built for smaller
amounts of capital. It should be remembered that the correct setup
of a firewall (commercial or homegrown) requires a significant amount
of skill and knowledge of TCP/IP. Both types require regular
...
... TCP/IP. Both types require regular
maintenance, installation of software patches and updates, and
regular monitoring. When budgeting for a firewall, these additional
costs should be considered in addition to the cost of the physical
...
...
As an aside, building a "home grown" firewall requires a significant
amount of skill and knowledge of TCP/IP. It should not be trivially
...
...
A final note about firewalls. They can be a great aid when
implementing security for a site and they protect against a large
...
...
Although they provide convenient access to a site for its users, they
can also provide an effective detour around the site's firewalls.
For this reason it is essential to maintain proper control of modems.
...
... B. Chapman and E. Zwicky, "Building Internet Firewalls", O'Reilly and Associates, Sebastopol, CA, 1995. ...
... W. Cheswick and S. Bellovin, "Firewalls and Internet Security: Repelling the Wily Hacker", Addison-Wesley, Reading, MA, 1994. ...
... NCSA, "NCSA Firewall Policy Guide", 1995. ...
... M. Ranum, "An Internet Firewall", Proceedings of World Conference on Systems Management and Security, 1992. ...
... M. Ranum, "A Network Firewall", Digital Equipment Corporation Washington Open Systems Resource Center, June 12, 1992. ...
... M. Ranum, "Thinking About Firewalls", 1993. ...
... M. Ranum and F. Avolio, "A Toolkit and Methods for Internet Firewalls", Trustest Information Systems, 1994. ...
... G. Treese and A. Wolman, "X Through the Firewall, and Other Applications Relays", Digital Equipment Corporation, Cambridge Research Laboratory, CRL 93/10, May 3, 1993. ...