It is quite easy to take a TCP connection down using a RST attack, and this risk increases with applications that need long-term connections, such as VPNs, DNS zone transfers, and BGP. We’ll describe how a TCP attack can happen, and we’ll show you some simple techniques for protecting your network.

Permanent mobile Internet access might sound like a nightmare for some, but for others it is a dream come true. All you need is Linux and a fairly recent mobile phone.

Despite the cyclical disruptions so typical of LUG meetings, our intrepid columnist, Charly, reveals how he set the system time in spite of a blocked NTP port.

Socks is a universal proxy protocol for TCP and UDP that allows internal hosts to securely pass the firewall and authenticates users. This article describes the latest version of the Socks proxy protocol and shows how to implement it.

Any user on a LAN can sniff and manipulate local traffic. ARP spoofing and poisoning techniques give an attacker an easy way in.

Security experts are always concerned with WLAN access points, but they sometimes forget that the client is also open to attack. Public hotspots make it quite easy for attackers to hijack connections, as the Hotspotter tool demonstrates.

In last month’s issue of Admin Workshop, we introduced tools that help admins get services up and running. This month, we will show how you can use the Ident protocol to associate a user name with a TCP connection.