TCP echo server using ncat

 ncat  -v -l -c 'while true; do read i && echo [echo] $i; done'  10.50.2.104 3000

UDP Client and Echo Server using netcat. for IPv6.

Client

nc -zuv6 2001:470:c2d7:917::38 3000

Server

nc -6lu 2001:470:c2d7:917::38 3000