After installing the new Eclipse 3.6M7 Stream Stable Build I could not connect to any update site nor to another project site.

After some investigation I found out that there must be something wrong with the used IP protocol stack. Eclipse seems to use IP4

So if you start eclipse with

./eclipse -vmargs -Djava.net.preferIPv4Stack=true

eclipse should be able to reach your update sites.

A small update to my Post:

I just found out that the real problem is a new  sysctl-setting under /etc/sysctl.d/bindv6only.conf. LOL

Check the net.ipv6.bindv6only item this should be 0 (null).

After changing reset the sys kernel variabels with:

sudo invoke-rc.d procps restart

have fun