[rmax] - April 2005 This little tool takes a list of IPv4 addresses on the command line, and calculates the respective IPv6 address prefixes for the 6to4 network. Example usage: $ 6to4 10.0.0.1 192.168.22.33 10.0.0.1 -> 2002:a00:1:: 192.168.22.33 -> 2002:c0a8:1621:: proc 6to4 {addr} { set octets [split [string trim $addr] .] if {[llength $octets] != 4} { return -code error \ "\"$addr\" does not consist of 4 octets separated by dots" } foreach octet $octets { if {![string is integer $octet] || $octet < 0 || $octet > 255} { return -code error "\"$octet\" is not a valid octet" } } foreach {a b} $octets { lappend words [expr {($a<<8) | $b}] } eval [linsert $words 0 format "2002:%x:%x::"] } foreach v4addr $argv { catch {6to4 $v4addr} v6addr puts "$v4addr -> $v6addr" } ---- [[ [Category Internet] ]]