ip address

MAC Filtering (layer 2 address filtering) refers to a security access control methodology whereby the 48-bit address assigned to each network card is used to determine access to the network. Iptables, pf, and IPFW can block a certain MAC address on a network, just like an IP. One can deny or allow from MAC address like 00:1e:2a:47:42:8d using open source firewalls. MAC address filtering is often used to secure LAN or wireless network / devices. Is this technique effective?


There is a program called Ping Tunnel to send TCP traffic over ICMP. From the project home page: Ptunnel is an application that allows you to reliably tunnel TCP connections to a remote host using ICMP echo request and reply packets, commonly known as ping requests and replies. At first glance, this might seem like […]

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If you need to calculate subnet under Linux use an IP Netmask/broadcast calculator called ipcal. You can calculate IPv4 or IPv6 address. Supported features: => Multiple address and netmask input formats. => Retrieving of address information from interfaces. => Classfull and CIDR output. => Multiple address and netmask output formats (dotted quad, hex, number of […]


Recently updated/posted Linux and UNIX FAQ: => Shell command or script to write simple output on screen under Linux and UNIX => Delete a log files in Linux or UNIX => VSFTPD limit the number of simultaneous vsftpd connections for a single IP address => Gnome Desktop Keyboard Shortcut Keys => Disable Advanced power management […]


So how do you restrict or deny access by IP address using Lighttpd web server? Lighttpd has mod_access module. The access module is used to deny access to files with given trailing path names. You need to combine this with remoteip conditional configuration. Syntax is as follows: $HTTP["remoteip"] == “IP” : Match on the remote […]


Explains how to bind Qmail SMTP to particular IP address.