In the last issue we started following a packet's journey from the wire up to the higher levels of network stack processing. We left the packet at the end of layer 3 processing, where IP has ...

So unlike static packet filtering (an earlier technology) which examined packets based on the information in their header, stateful inspection can actually track each connection across all interfaces ...

When deciding on a firewall implementation, most Unix-savvy administrators have usually chosen to use ipfilter on OpenBSD for their combination of capabilities and stability, as the capabilities of ...

Learn how firewalls have progressed from simple packet filtering to more sophisticated application-level filtering. Webopedia.com defines a firewall as “a system designed to prevent unauthorized ...

Filters can permit or deny virtually any kind of traffic – up to a point. Here are some basic dos and don’ts for filter usage. Filters can permit or deny virtually any kind of traffic – up to a point.

Network geeks among you may remember my article, “Linux Socket Filter: Sniffing Bytes over the Network”, in the June 2001 issue of LJ, regarding the use of the packet filter built inside the Linux ...