On Wed, Jul 26, 2006 at 10:00:19AM +0800, dxuranus wrote: > i have a public hostname "a" (not my machine name)on internet and my > ip is xx.xx.xx.xx; > the problem is other people can get my ip through hostname.but if he > try to get my hostname through ip he always failed. > the case above is in my program (i make it) ,what can i do for this? This is not a CentOS issue. You need your ISP to set your "reverse DNS". Depending on your ISP, they may not do this for customers at all. -- Matthew Miller mattdm at mattdm.org <http://mattdm.org/> Boston University Linux ------> <http://linux.bu.edu/>