[host@test ~]# ping 10.0.0.1
PING 10.0.0.1 (10.0.0.1) 56(84) bytes of data.
64 bytes from 10.0.0.1: icmp_seq=1 ttl=64 time=0.023 ms
[host@test ~]# telnet 10.0.0.1 666
Trying 10.0.0.1 ...
telnet: connect to address 10.0.0.1 : Connection refused
telnet提示Connection refused的可能是什么