Birmingham mumbai

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The entry for 
mail
 is special as it is not an address record, but instead a 
Canonical 
Name
 (
CNAME
) record. In this case, it just points back to 
mailserv
. Essentially, 
that's what a CNAME record does: it creates a pointer to another resource. In this 
case, if someone tries to access a server named 
mail
, we redirect them to the actual 
server 
mailserv
. Notice that on the CNAME record, we're not inputting an IP 
address, but instead the hostname of the resource it's linked to.
In addition, you should also notice that I added the DNS server itself (
hermes
) to the 
file as well. You can see it on the second line above. I've found that if you don't do 
this, the DNS server may complain and refuse to load the file.
Now that we have a zone file in place, we should be able to start using it. First, 
we'll need to restart the 
bind9
 service:
sudo systemctl restart bind9 
After the command finishes, check to see if there are any errors:
systemctl status bind9 
You should see that the service state is 
active (running)
, and in addition, you 
should see a line telling you that the serial number for your zone file was loaded. If 
you see that the service is not running and/or your zone file was not loaded, you 
should see specific information in the output while checking the status that should 
point you in the right direction. If not, you can also check the system log for clues 
regarding 
bind
 as well:
cat /var/log/syslog | grep bind9
The most common mistakes I've seen typically result from not being consistent 
within the file. For example, if you're using a different IP scheme (such as 
10.10.10.0/24
), you'll want to make sure you didn't forget to replace any of my 
example IP addresses with the proper scheme. Assuming that everything went 
smoothly, you should be able to point devices on your network to use this new 
DNS server. Make sure you test not only pinging devices local to your network, but 
outside resources as well, such as websites. If the DNS server is working properly, 
it should resolve your local names, and then forward your requests to your external 
DNS servers (the two we set as forwarders) if it doesn't find what you're looking 
for locally. In addition, you'll also want to make sure that port 
53
 is open in your 
network's firewall, which is the port that DNS uses. It's extremely rare that this 
would be an issue, but I have seen it happen.

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Setting Up Network Services