Birmingham mumbai

Start of Authority
 (
SOA
) line, we're establishing that our DNS server is 
authoritative over the 
local.lan
 domain:
@ IN SOA local.lan. hostmaster.local.lan. ( 
We also set 
[e-mail]
 as the email address of the responsible party for 
this server, but we enter it here in a different format for 
bind
 (
hostmaster.local.
lan
). This is obviously a fake address, but for the purposes of an internal DNS server, 
its validity is of no concern.
Of all the lines of configuration within a zone file, 
serial
 is by far the one that will 
frustrate us the most:
202008161; serial 
This is because it's not enough to simply update the zone file any time we make a 
change to it (change an IP address, add or remove a host, and so on); we also need 
to remember to increase the serial number by at least one. If we don't, 
bind
 won't be 
aware that we've made any changes, as it will look at the serial number before the 
rest of the file. The problem with this is that you and I are both human, and we're 
prone to forgetting things. I've forgotten to update 
serial
 many times and have 
become frustrated when the DNS server refused to resolve new hosts that were 
recently added. Once I remembered that I didn't increment the serial number, the 
issue was resolved after I did. Therefore, it's very important for you to remember 
that any time you make a change to any zone file, you'll need to also increment the 
serial number. 

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Setting Up Network Services