I have solved another IPv6 problems on Ubuntu Lucid 10.04. When trying to install a package (apt, aptitude or synaptic) wget has these symptoms;
--2010-05-21 20:05:55-- http://internap.dl.sourceforge.net/sourceforge/corefonts/webdin32.exe
Resolving internap.dl.sourceforge.net... 1.0.0.0
Connecting to internap.dl.sourceforge.net|1.0.0.0|:80... failed: Connection timed out.
Giving up.
This example was when I was trying to download the fonts but I have seen it on several different attempted installs. It has been reported as a wget issue or a DNS Cache issue, but I am pretty certain it is an IPv6 issue, probably with the way the AAAA address is interpreted.
Anyway the solution is simple. Open up /etc/wgetrc as sudo and add this line at the end
inet4-only = on
That should solve it. It does the same as my earlier post but is a permanent solution.