stateful inspection


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stateful inspection

A firewall technology that ensures that all inbound packets are the result of an outbound request. Also called "stateful packet inspection" (SPI), it was designed to prevent harmful or unrequested packets from entering the computer. For example, if you click on a link to a Web page, an HTTP request is being made to a specific URL address. All packets coming back from that URL would pass the stateful inspection and be accepted. Every so many minutes, your email program queries the mail server, and returning packets from that server are allowed.

Essential and Problematic
Stateful inspection is the norm and generally a major component in every network firewall and personal firewall. However, stateful inspection causes problems with videoconferencing and VoIP, in which a user outside the network wants to initiate a communication with a user inside the network. Various techniques are used to work around this (see STUN, UPnP and port forwarding). See firewall.
References in periodicals archive ?
At its headquarters and each of its six branch sites, DIV uses the Unified Threat Management (UTM) security features of the NetScreen-5GT firewall, which includes stateful inspection firewall, IDP, Antivirus (Anti-Spyware, Anti-Phishing, Anti-Adware), Anti-Spam, and Web Filtering functions to protect DIV's network from external attacks.
Check Point VPN-1 UTM Edge is an all-in-one security appliance with integrated stateful inspection firewall, intrusion prevention, gateway antivirus and IPSEC VPN that can be deployed in minutes to securely connect hosted networks without on-site IT staff and without additional equipment to purchase.
With all-in-one security -- powerful stateful inspection firewall, industrial strength intrusion prevention, gateway antivirus and IPSEC VPN, VPN-1 UTM Edge also contains wide support for ADSL and WLAN protocols to provide companies with the most flexibility and interoperability in deployment.