diff --git a/client.go b/client.go
index 3b734ac..62d4fcd 100644
--- a/client.go
+++ b/client.go
@@ -8,40 +8,6 @@ import (
 	"time"
 )
 
-func (c *Client) setNick(nick string) {
-	//Set up new nick
-	oldNick := c.nick
-	oldKey := c.key
-	c.nick = nick
-	c.key = strings.ToLower(c.nick)
-
-	delete(c.server.clientMap, oldKey)
-	c.server.clientMap[c.key] = c
-
-	//Update the relevant channels and notify everyone who can see us about our
-	//nick change
-	c.reply(rplNickChange, oldNick, c.nick)
-	visited := make(map[*Client]struct{}, 100)
-	for _, channel := range c.channelMap {
-		delete(channel.clientMap, oldKey)
-
-		for _, client := range channel.clientMap {
-			if _, skip := visited[client]; skip {
-				continue
-			}
-			client.reply(rplNickChange, oldNick, c.nick)
-			visited[client] = struct{}{}
-		}
-
-		//Insert the new nick after iterating through channel.clientMap to avoid
-		//sending a duplicate message to ourselves
-		channel.clientMap[c.key] = c
-
-		channel.modeMap[c.key] = channel.modeMap[oldKey]
-		delete(channel.modeMap, oldKey)
-	}
-}
-
 func (c *Client) joinChannel(channelName string) {
 	newChannel := false
 
diff --git a/server.go b/server.go
index b4ce0bd..0cf3a03 100644
--- a/server.go
+++ b/server.go
@@ -94,31 +94,8 @@ func (s *Server) handleCommand(client *Client, command string, args []string) {
 	case "VERSION":
 		client.reply(rplVersion, VERSION)
 	case "NICK":
-		if len(args) < 1 {
-			client.reply(errNoNick)
-			return
-		}
-
-		newNick := args[0]
-
-		//Check newNick is of valid formatting (regex)
-		if nickRegexp.MatchString(newNick) == false {
-			client.reply(errInvalidNick, newNick)
-			return
-		}
-
-		if _, exists := s.clientMap[strings.ToLower(newNick)]; exists {
-			client.reply(errNickInUse, newNick)
-			return
-		}
-
-		//Protect the server name from being used
-		if strings.ToLower(newNick) == strings.ToLower(s.name) {
-			client.reply(errNickInUse, newNick)
-			return
-		}
-
-		client.setNick(newNick)
+		client.reply(rplKill, "Can't change nicks on this server", "")
+		client.disconnect()
 
 	case "USER":
 		if client.nick == "" {