comida is a bash script designed to create a FTP (or HTTP, or rsync or…) mirror and maintain the archive synchronized with the source. I design this tool when I was working at the Free Software Office (OSL) in the University of A Corunna, and decided to create a new mirror in Spain which host a lot of free software projects. But, we wanted a single tool to manage all mirrors in the archive, with full integration in our web page (yes, we wanted on-the-fly status page).
You can download the source code from launchpad project page or using bzr version control system:
$ bzr get lp:comida
tcptraceroute was another friend of the network administrator. Probably you known classical traceroute, which use the TTL field in IP header to determinate the hops in the route to a specific destination. In each hop the TTL value is decreasing (according to internet protocol), and when TTL is equal to cero, a ICMP is returned to sender IP. So, the classical traceroute technique, send a UDP packet with TTL field setted to 1, and get the IP address of the first hop from returned ICMP, and likewise for other hops.
Unfortunately, today many host are firewalled and ICMPs are blocking. The classical traceroute design fails, and we only obtain a list of useless “*”. The tcptraceroute use TCP packets instead of UDP packets, and try to connect to usual port enabling the SYN flag. If port is closed, a RST flag is returned, and if port is open then return an ACK flag. So we don’t need ICMPs anymore.