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Topic: Stateful firewall


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NAT

  
  React Technologies - wireless networking, wireless lan switching, firewall, voip, vpn.
Stateful inspection firewalls protect against unauthorized users accessing network resources and the unauthorized use of network resources.
A stateful inspection firewall accepts or denies traffic based on the source IP address, destination IP address, source port, destination port and protocol.
Firewall configuration can be simpler than ACL configuration for this reason, since the administrator does not need to worry about building consistent input and output AC Ls.
www.reacttechnologies.com /StatefulFirewall.html   (366 words)

  
 dmiessler.com | study | firewalls
A stateful firewall differs from a standard packet filter in a very simple way -- a stateful firewall deals with connections and their characteristics rather than packets individually.
Another thing that stateful inspection brought to the table was the ability to touch the application layer to some degree.
Firewall vendors have hyped the term to the point that it carries almost magical overtones.
dmiessler.com /study/firewalls   (1456 words)

  
 Firewall Evolution - Deep Packet Inspection
Stateful inspection provides for the analysis of packets at the network layer as well other layers (typically the transport layer in the OSI model but the firewall may look at layers above that as well) in order to assess the overall packet.
For most stateful firewalls the establishment of the connection and the monitoring of it for when connection is terminated is sufficient.
The firewall, because it is capable of Deep Packet Inspection, is able to identify the exploit attempt and deny the connection.
www.securityfocus.com /infocus/1716   (1575 words)

  
 What is stateful inspection? - A Word Definition From the Webopedia Computer Dictionary
Stateful inspection is a firewall architecture that works at the network layer.
Unlike static packet filtering, which examines a packet based on the information in its header, stateful inspection tracks each connection traversing all interfaces of the firewall and makes sure they are valid.
An example of a stateful firewall may examine not just the header information but also the contents of the packet up through the application layer in order to determine more about the packet than just information about its source and destination.
www.webopedia.com /TERM/S/stateful_inspection.html   (277 words)

  
 CyberGuard: Premium Firewall / VPN Appliances   (Site not responding. Last check: 2007-10-11)
A firewall can be network hardware or even software running on your PC that controls how packets of network data pass through or into your computer.
This can be a very good thing because a hacker trying to gain access through a firewall has less chance of forging entry as part of a valid series of connections because the state tables show that the additional connection does not make sense in the context of the legitimate user.
SnapGear VPN Firewall Appliances incorporate PPTP and IPSec VPN protocols and all SnapGear units are able to act as a server or client (that is, they can either initiate or accept VPN tunnel connections).
www.cyberguard.info /snapgear/firewall.html   (908 words)

  
 Stateful Inspection Firewall
With stateful inspection, packets are intercepted at the network layer for best performance (as in packet filters), but then data derived from all communication layers is accessed and analyzed for improved security (compared to layers 4–7 in application-layer gateways).
Stateful Inspection then introduces a higher level of security by incorporating communication- and application-derived state and context information which is stored and updated dynamically.
All traffic passing through the firewall is analyzed against the state of these connections in order to determine whether or not it will be allowed to pass through or rejected.
www.ssimail.com /Stateful.htm   (999 words)

  
 SonicWALL - Firewall   (Site not responding. Last check: 2007-10-11)
Stateful Packet Inspection - Stateful Packet Inspection is a smarter form of packet filtering, which inspects headers of network "packets." It blocks any packet arriving at the firewall claiming to be a solicited response.
Stateful inspection technology tracks each packet traversing the firewall and makes sure that they are legitimate.
A stateful inspection firewall also monitors the state of the connection and compiles the information in a state table ensuring that the source and destination of each packet is valid.
www.sonicwall.com /applications/firewall.html   (983 words)

  
 Paranoid Penguin - Application Proxying with Zorp, Part I
A firewall, of course, is a computer or embedded hardware device that separates different networks from one another and regulates what traffic may pass between them.
Second, because the firewall is re-creating the client connection in its entirety and not merely propagating or trivially rewriting individual packets, the firewall is well positioned to examine the connection at the application layer.
This is not a given, however; if the firewall is, say, a SOCKS firewall and not a true application-layer proxy, it simply could copy the data payloads of the client connection packets into those of the new, proxied packets.
www.linuxjournal.com /node/7296/print   (2369 words)

  
 Stateful Packet Inspection and Stateful Inspection Firewalls
Stateful packet inspection, a firewall technology invented by Check Point Software Technologies in the early 1990s is also known as dynamic packet filtering.
Stateful inspection keeps track of communications packets over a period of time, while the traditional static packet filtering only one packet is examined at a time.
Stateful inspection firewalls (SIFs) would not just verify that a DNS response corresponded to a request, but would examine the contents of the request and the response and would confirm that the response does indeed conform with what the questioner asked for.
www.networkdictionary.com /security/StatefulPacketInspection.php   (389 words)

  
 Stateful firewall - Wikipedia, the free encyclopedia
In computing, a stateful firewall (any firewall that performs stateful packet inspection or stateful inspection) is a firewall that keeps track of the state of network connections (such as TCP streams, UDP communication) traveling across it.
The stateful firewall depends on the famous three-way handshake of the TCP protocol.
Today, firewalls are again using application level filters called proxies — or application level proxies because machines with modern CPU speeds are capable of doing deep packet inspection in reasonable time.
en.wikipedia.org /wiki/Stateful_firewall   (968 words)

  
 Feature: A Stateful Inspection of FireWall-1
The payload of this packet was a PORT command, which the firewall's FTP stateful inspection module interpreted as a legitimate data connection that needed to be passed through the firewall.
It is important to note that the firewall does not attempt to tear down the connection; it only removes its entry in the connection table and drops any subsequent packets.
When the first data packet of the RSH connection is passed by the firewall, its entry in the pending table is replaced with a new one, containing the source IP address, the error port (extracted from the TCP payload), the destination IP address, the same magic number, and the IP protocol.
www.rootprompt.org /article.php3?article=868   (3715 words)

  
 RIK FARROW'S 1997 FIREWALL PRODUCT ANALYSIS
The firewall should function at the level required by your policy for authenticating traffic, collecting sufficiently detailed logging, and perhaps inspection of data which passes (for viruses or applets).
Firewall technologies vary as to each one's strengths and weaknesses, and it is up to you to choose the right technology and vendor.
Stateful inspection only needs to compare the first packet in a connection to the rule set, and if the packet is permitted, adds information, the state, to an internal database.
www.spirit.com /CSI/Papers/farrowpa.htm   (1878 words)

  
 Inside Network Perimeter Security: Stateful Firewalls > How a Stateful Firewall Works   (Site not responding. Last check: 2007-10-11)
The focus of this chapter is on stateful firewalls, a type of firewall that attempts to track the state of network connections when filtering packets.
The stateful firewall's capabilities are somewhat of a cross between the functions of a packet filter and the additional application-level protocol intelligence of a proxy.
If the inspected packet matches an existing firewall rule that permits it, the packet is passed and an entry is added to the state table.
www.informit.com /articles/article.asp?p=373431   (827 words)

  
 Stateless firewall - Wikipedia, the free encyclopedia
In computing, a stateless firewall is a firewall that treats each network frame (or packet) in isolation.
Since a firewall has no way of knowing that the packet destined to the protected network, to some host's port 4970, is part of a legitimate FTP session, it will drop the packet.
Stateful firewalls solve this problem by maintaining a table of open connections and intelligently associating new connection requests with existing legitimate connections.
en.wikipedia.org /wiki/Stateless_firewall   (290 words)

  
 Personal Firewall Behavior
The firewalls tested were the XP Built-in Firewall and the Cisco VPN Client's "Stateful Firewall".
To be fair, if the firewall did allow this huge range to be excepted, there would be little reason to have a firewall at all, since essentially most inbound traffic would be allowed.
Many firewalls will allow incoming data to a port if it is returning in response to an outgoing request on that same port.
www.itc.virginia.edu /videoconf/firewall.html   (973 words)

  
 Firewall Setup - SBLUG   (Site not responding. Last check: 2007-10-11)
The firewall does not know that the incoming packets from port 80 (http response) are related to the outgoing packet that was sent to port 80 (http request).
In a Stateful firewall there is some relationship established between the outgoing and incoming packet streams.
refers to the stateful connection tracking in the 2.4 and 2.6 kernels and is used when a connection isn't on the same connection, but is used with the same connection, such as an FTP connection.
wiki.sblug.org /Firewall_Setup   (1759 words)

  
 HOWTO Iptables and stateful firewalls - Gentoo Linux Wiki
Our firewall is going to run on a Linux laptop, workstation, server, or router; its primary goal is to allow only certain types of network traffic to pass through.
The RELATED state can be used to regulate connections that are part of a multi-connection protocol, such as ftp, as well as error packets related to existing connections (such as ICMP error packets related to an existing connection).
Rather than let potential intruders know that we're running a firewall (and thus tip them off to the fact that we may be running some valuable services that they can't get to), it would be to our advantage to make it appear as if we aren't running any services at all.
gentoo-wiki.com /HOWTO_Iptables_and_stateful_firewalls   (5592 words)

  
 NetworkShield Firewall 2006 - Corporate Gateway Firewall
NetworkShield Firewall 2006 is a new generation corporate gateway firewall, which protects the network from external and internal attacks, provides Internet access to users and offers enhanced traffic control features.
NetworkShield Firewall 2006 is extremely easy to install and set up using intuitive configuration wizards and an advanced control panel.
One of the main advantages of NetworkShield Firewall 2006 is its powerful and stable engine for processing and controlling the network traffic.
www.networkshield.com   (159 words)

  
 Firewall Setup   (Site not responding. Last check: 2007-10-11)
The main file firewall.conf uses the defined variables in firewall.setup (needs to be modified), to allow the same configuration file to be used in multiple situations.
It then calles firewall.users_config (needs to be modified, if you like to change the number of users) which in turn delicates some ipfw firewall rules to firewall.user in order to reuse the ipfw firewall rules it contains.
The FreeBSD firewall setup is done during the next boot by loading the ipfw firewall rules with the given flags.
alex.kruijff.org /FreeBSD/Firewall_Setup.html   (1593 words)

  
 Firewall trial - Firewall demo - Firewall Internet free download
Firewall - NT Kernel Resources NeT FirewallNeT Firewall is a comprehensive stateful firewall solution built to protect Windows-based systems not currently protected by a firewall [more]
Firewall - Outpost Firewall Pro - world's foremost protection application, providing a superior arsenal of defense against PC infiltration.
Firewall Keywords: personal firewall :: firewall software :: xp firewall :: windows xp firewall :: pc firewall :: personal firewall software :: pop up stopper :: spyware remover :: inte
trialfreedownload.com /Firewall   (660 words)

  
 Stateful Firewall and Masquerading on Linux (Stateful Packet-Filtering Firewall)
Since the stateful firewall filter is not a built-in feature, a so called "match extension" must be invoked.
This is a new connection which is related to the connection that you initiated by connecting to port 21 on the FTP server.
To use the system as a firewall and gateway for other servers on the local network, Netfilter needs to be told to accept all new network packets coming from the local network.
www.puschitz.com /FirewallAndRouters.shtml   (1276 words)

  
 Lightspeed Firewall - Lightspeed Systems
Generally considered "state of the art" firewall technology, stateful packet inspection is a technology similar to that used by the industry-leading products.
Lightspeed Firewall monitors traffic flowing past the wire; inspects the traffic-whether packets or flows-for matches to known rule sets; and when there is a match takes whatever action you have specified.
Lightspeed Firewall includes detailed real-time and recorded stats that tell the network administrator the status of their network at any moment, or trends over days or weeks.
www.eratefirewall.com /layers.asp   (567 words)

  
 Re: stateful firewall
Basically stateful firewalls allow more complex things to be done more simply.
This means it's more difficult to write the code to implement a stateful packet filter, but much easier to write the firewall rules.
With a stateful packet filter that understands the FTP protocol, you can just tell it to allow FTP connections and not have to open up huge ranges of ports that actually have nothing at all to do with FTP, but could be used in transferring FTP data.
lists.debian.org /debian-firewall/2001/03/msg00064.html   (459 words)

  
 Software Firewall - VisNetic Firewall
Stateful inspection firewalls determine whether packets can get through the firewall based on the protocol, port, and source and destination addresses.
For every request that is allowed by this strategy, stateful inspection firewalls open up a limited time window to allow response packets, but ONLY from the same host.
VisNetic Firewall detects the seven most common forms of port scans, alerting you with a log entry and optionally automatically banning the IP address of the scanner, ensuring that they are "cut off" before they can discover any useful information about your system.
www.deerfield.com /products/visnetic-firewall/features   (399 words)

  
 SonicWALL Firewall Features
SonicWALL firewall's connectivity features provide end-users with implementation alternatives that are within their scope of expertise and cost parameters.
The firewall's superior performance is the result of its Stateful Inspection Technology.
This unique architecture applies stateful inspection at the lowest layer of the protocol stack, allowing only packets permitted by the firewall strategy to enter the network.
www.ssimail.com /Guardian.htm   (679 words)

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