Bug#319017: It is an hardware problem related to IPv6
I too have the same problem. After some debugging I have found out that it is an harware problem of the ADSL-router D-Link DSL-G604T when IPv6 is involved.
I-ll give belove a workaround and a request that an option is inserted into the installation process so that an option to stick to IPv4 is passed to any called program.
Even if it is an hardware problem I would raccomend to keep this bug inside the installation bugs, becouse it is a serious problem for the people wanting to install.
I have figure out that the problem of resolving the IP asddress came out only with some programs and that if the IP was already got by a previous program.
So the workaround I used is to go to a shell prompt (pressing CTRL+ALT+F2 and than logging) and I made a ping to the same host, then I tried to telnet to the port 80 of the same server and I saw it worked ( write telenet "xxx.yyy 80" , where xxx.yyy is the site name to telnet on the 80th port, then to close the connection press CTRL+] and write close).
Then I returned to the installation windows (pressing CTRL+ALT+F1) and the installation worked.
However sometimes (and I can tell you when) only one IP address is kept and if another site is pinged the previous one is no more reachable. This may result that you are not able to connect to security.debian.org (that, by the way, the user is not able to retry).
But this is just a workaround. It would be better (and this is a note to everybody involved in installation) if the installation program had an option to stick to IPv4.
This would be useful not only in this specific case, but in any case when old or buggy (that is that are not able to handle IPv6 request) hardware or software are involved.
I have seen that telnet has an option (-4) that stick the IP resulution to IPv4 (thae man page says "Force IPv4 address resolution"). I do not know if all the other programs involved into installation have a similar option. It would be nice if they have it and if the installation program has a way to pass this option to the programs involved in installation process.
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