To enable Telnet Server please follow below steps :
Fedora core 16 Server as telnet server:
1) yum install telnet-server
2) vim /etc/xinetd.d/telnet
service telnet
{
disable = no
flags = REUSE
socket_type = stream
wait = no
user = root
server = /usr/sbin/in.telnetd
log_on_failure += USERID
flags = IPv6
}
Change disable to "no" and add "flags=IPv6"
3) systemctl restart xinetd.service
Fedora Core 11 Client
telnet ipv6address%interface-name
Telnet clients supports ipv6 but if you do not specify interface-name in the command , "invalid argument" error will be displayed in clients, when you try to telnet.
telnet fe80::1e63:45ff:fec4:8823%eth1
and
telnet ipv4-address
telnet 192.167.23.2
Both command should work fine.