Birmingham mumbai

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Feel free to edit this file to match your configuration. You can edit the list of 
hosts at the end of the file to match your hosts within your network, as the ones I 
included are merely examples. You should also ensure that the file matches the IP 
scheme for your network. Next, I'll go over each line in order to give you a deeper 
understanding of what each line of this configuration file is responsible for:
$TTL 1D 
The 
Time to Live
 (
TTL
) determines how long a record may be cached within a DNS 
server. If you recall from earlier, where we practiced with the 
dig
 command, you 
saw that the second time you queried a domain with 
dig
, the query time was less 
than the first time you ran the command. This is because your DNS server cached the 
result, but it won't hold onto it forever. At some point, the lookup will expire. The 
next time you look up that same domain after the cached result has expired, your 
server will go out and fetch the result from the DNS server again. In my examples, I 
used Google's DNS servers. That means at some point, your server will query those 
servers again once the record times out.
With the