新增第二個shard時報錯

根據http://www.linuxidc.com/Linux/2011-11/47460.htm 帖子設定, 在最後加第二個shard時報錯, 請各位幫幫忙:
db.runCommand( { addshard : “shard2/192.168.112.172:27018,192.168.112.173:27018,192.168.112 .174:27018″,name:”s2”,maxsize:20480} );
{
“ok” : 0,
“errmsg” : “couldn’t connect to new shard socket exception [CONNECT_ERROR] for shard2/192.1 68.112.172:27018,192.168.112.173:27018,192.168.112.174:27018”
}