Telnet Hacking

I've made a TCP/IP port scanner in C and I found out the open ports on a remote host..If port 23 is not open, Is there any use in telnetting to another port so that it can be hacked?

 

can u add more clarity in your questions
thanks.

 

except port 23 you can telnet on other ports such as port 25 which is the smtp protocol.

 

absolutely,do some research on specific commands for diff. ports. I had accessed servers thru telnet in diff. ports. It will all depend on how secure it is,the rfirewall,if it's passworded ect.

 

well, can u share your code for making that scanner in c?