Saturday, July 23, 2005

Internal DNS


I just noticed something interesting.  Since we use DHCP in out network, I was curious what ip address were allocated to the devices on my network.  So I ran the following command:



nmap -sP 192.168.1.0/24


I noticed something interesting.  A lot of the machines have fully qualified domain names.  I was curious why this was happening, especially since I didn't create these entries.




About a week ago, I updated to the latest version of the sveasoft firmware for my Linksys WRT54GS.  It looks like when this version allocates an ip address, it takes note of the host name and then creates a dns entry for it. This works perfectly if the client using dhcp does not specify dns servers, then the computers will default to using the router as the dns server.


This is great because now I can use a host name to access any machine that gets it's ip address from dhcp.


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