Telnet connection with echo service succeeds for localhost and 127.0.0.1 host names, but fails with ::1 host name:
alex@u120432:~$ telnet localhost 7
Connected to localhost.
Escape character is '^]'.
alex@u120432:~$ telnet ::1 7
telnet: Unable to connect to remote host: Connection refused
My own program also fails, trying to talk using IPv6 address. Why IPv6 address is rejected?
OS: Ubuntu 12.04 32 bit.
For any TCP/UDP server-client programs (not only telnet + echo) I tried different host names. Assuming that computer IP address is 10.90.185.73 (fe80::21b:21ff:fe5e:28af), I tested the following options:
localhost - works
127.0.0.1 - works
::1 - Connection refused
10.90.185.73 - works
computer-name - works
::ffff:10.90.185.73 - works
fe80::21b:21ff:fe5e:28af - Connection refused