C:\>nslookup us.rr.efnet.net
Server: spr3.nsw-remote.bigpond.net.au
Address: 61.9.192.13

*** spr3.nsw-remote.bigpond.net.au can't find us.rr.efnet.net: Non-existent domain

Try another Efnet server, such as irc.prison.net.