4086b04e   
   XPost: comp.os.ms-windows.networking.tcp-ip   
   From: m@rtij.nl.invlalid   
      
   On Wed, 12 Aug 2009 00:58:15 -0700, S Claus wrote:   
      
   > Hi all,   
   >   
   > here is a perhaps dumb question about hostnames on a company network.   
   >   
   > At this place where I work we have servers that can be pinged using:   
   >   
   > ping SMTAPPU01   
   >   
   > ...yet the ping starts with the statement: Pinging ldncsr0988.intra...   
   > [nn.nnn.n.n]   
   >   
   > And I can also using:   
   >   
   > ping ldncsr0988   
   >   
   > which gives the same reply.   
   >   
   > My question about this is, is it NAT that is used to have a server have   
   > two hostnames?   
      
   No, it's simple. There is DNS to map a name to an IP address. Multiple   
   names can legitimately map to one IP address.   
      
   Ping then uses reverse DNS to look up the name belonging to that IP   
   adress and shows that name.   
      
   These mappings are completely unrelated, it's up to the admin to make   
   sure that what reverse DNS returns, indeed is the canonical name for that   
   machine, but if misconfigured, it might return a completely different   
   name.   
      
   To make it a bit more complex, it is completely legitimate to reverse map   
   an IP address to multiple names. In fact, some argue that this was how   
   DNS was envisioned. But don't do that, it probably confuses a lot of   
   software and no one does it anyhow. Probably ping would still print the   
   first name in the list of names it gets back for that IP address, but   
   that is just guessing.   
      
   HTH,   
   M4   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)