I was having a discussion with someone who said that
telnet, FTP, HTTP plain-text authentication in the local subnet is ok because it's a switched network. Also, that these protocols are not good over the net but in a local subnet they are just fine.

I know that someone can plug a hub in the network port and connect 2 (or more) PCs and see the packets. Also, heard about ettercap but haven't really delved into it. I know dsniff was written to prove the point that unencrypted protocols are bad.

Would like to get opinion about unencrypted protocols over a switched networks.

Thanks.

bad dont use them. arp poisoning can still be used to intercept traffic on a switched network. there can be mitigating factors, but in this day and age, there is a easy-to-deploy, secure alternative in probably every case.