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.

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.

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.

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.

Networks often require very accurate timekeeping. The Network Time Protocol provides the time with precision.

If you need a tool for filtering protocols that doesn’t depend on the port, try L7, an IPTables patch that operates through regular expressions.