I confirm same kind of problem in Precise.
After update to -ubuntu6.10 ipv4 become to be preferable protocol even on ipv6-only servers.
%%
telnet google.com 443
Trying 173.194.222.102...
Trying 173.194.222.101...
Trying 173.194.222.113...
Trying 173.194.222.138...
Trying 173.194.222.139...
Trying 173.194.222.100...
telnet: Unable to connect to remote host: Network is unreachable
%%
Direct protocol direction works fine:
%%
telnet -6 google.com 443
Trying 2a00:1450:4010:c01::65...
Connected to google.com.
Escape character is '^]'.
%%
I confirm same kind of problem in Precise. 4010:c01: :65...
After update to -ubuntu6.10 ipv4 become to be preferable protocol even on ipv6-only servers.
%%
telnet google.com 443
Trying 173.194.222.102...
Trying 173.194.222.101...
Trying 173.194.222.113...
Trying 173.194.222.138...
Trying 173.194.222.139...
Trying 173.194.222.100...
telnet: Unable to connect to remote host: Network is unreachable
%%
Direct protocol direction works fine:
%%
telnet -6 google.com 443
Trying 2a00:1450:
Connected to google.com.
Escape character is '^]'.
%%