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Hey guys and welcome back. In the previous nugget we had just began the configuration

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of our DNS zone. So you will recall that within this configuration file named d.conf.local

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we specified some database files that actually do not exist. So as such we're going to have

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to create them. So all I will do here is I'll just copy this right here and I will just

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say sudo touch to create this file. Type in my password. Again the reason why I'm saying

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sudo is because we are within the etsy bind directory. So within etsy we need to have

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super user privileges. And again with respect to the reverse zone file. Let's copy this

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and I'll say sudo touch. So now if I do an ls we actually have the file created for our

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forward zone as well as our reverse zone. Now these are just empty files right now.

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They do not configure or rather contain any configurations. So now we can actually begin

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populating these files with the correct content. But a good tip to actually start off is to

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use one of the already created files as a general template. So what I'm going to do is I'm going

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to go into this db.local file and all this is going to be is used as a skeleton template

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because our database file for our forward zone and the reverse zone is going to be quite

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similar to this with some basic modification. So what I will do here is I'm actually going

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to go out and I will say sudo cp and I will copy the local database file db.local and

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I'm going to copy it into my ipv0.com.db. So that's now copied. If I now go into my

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ipv0 file now we can see here it's basically just a copy of that db.local file. But like

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I say we're going to have to make some modification. Now there are some particular values we have

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to be aware of. The first value we can see here is the SOA. This is going to be the start

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of authority. This is going to tell us pretty much who is responsible for our domain as

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well as what our domain actually is. Right now it's saying here that the domain is local

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host that is not the configuration we want. So let's begin with some basic modifications.

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So what I'm going to do is I'm going to delete this and I'm going to give this server a particular

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name. We just call this my server dot and this is going to be within the ipv0.com domain

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and what I'm going to do at the very end I'm going to add on the period because the period

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actually is part of the fully qualified domain name. Now I'll specify who is responsible.

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This is going to be the root for that domain. So I will just say dot ipv0.com and again

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we want to be remembering that period at the very end of the domain name. Now we're going

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to see a bunch of these values. The first one here is serial. Now this can actually be

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an arbitrary value. We can see it's the value 2 right now but the value could be 1342. It

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doesn't actually matter what is important is that the actual value of the serial matches

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between my forward zone which is this configuration file right here ipv0.com dot db as well as

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the next configuration file. I'm going to be creating the reverse zone file. So we want

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to have the same value here. Have them to synchronize together. Now every time you make a change

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to this configuration file you want to increment this value. So if I happen to later on make a

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change to this file I would change it from 2 to maybe say 3 and then in the reverse zone match

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that up to. So right now I'm going to be making a change right now so I'll change this to 3. Now

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we also have additional information relating to our TTL how long information is going to be

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cached, how long we should wait for retries and expiration so on so forth but for now we will

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actually just skip ahead and just focus on that serial value by incrementing it and making sure

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we have the same value in the next configuration file we're going to be creating. But for now

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what I'm going to do is I'm going to go down here and this is where I can specify my particular

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record. So what I'm going to do here is I'm going to delete a whole bunch of this stuff right here

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and I delete this here. So this at symbol right here this is what I'm going to use to delineate

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these particular records and values. So I will say at in and then the type of record I want to

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create this is going to be for my name server. Now what is my name server actually going to be?

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It's going to be I specified my server ipv0.com and then again that dot at the very end. So I'll

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say my server dot my domain dot ipv0.com and then a dot again do not forget that. Now what I want

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to do is I want to correlate my server with a particular ip address. So within here I'm going

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to say my server and then I'll do my tab I'll do in tab and then the type of record this time is going

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to be an a record. Now you will remember that an a record correlates to an ipv4 address. So again

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I'll hit tab and now what I'll do here is specify the particular ipv4 address I want to correlate

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here. So I'll say 192.168.0.44 that is the ip address of my particular server here. Now what I'm

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going to do is to create another namespace just for demonstration for something that doesn't

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actually exist. So I'll just call this I don't know email server maybe and I'll tab I'll say in

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I'll make it an a record once again and I'll just specify an arbitrary ip address 192.168.0.50. I

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don't actually have this server on my network that doesn't actually matter right now I just want to

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be able to show you that we can have these records so that when we look at particular pieces of

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information they're going to resolve to the information we specify within this configuration

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file. So like I say I've created my server I have it here mapped to this ip address I have my actual

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domain here I have root.ipv0.com I'm making sure I have my periods at the end and I've just created

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also this arbitrary namespace for resolution just for the purposes of my testing. Again one

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thing we want to be remembering is this serial number I have it at the value 3. Now let's move

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on to the next file and in fact before I actually do that what I'm going to do here I'm going to

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copy from the TTL down to my semicolon here okay so I'll save this file I'll go out. Now what I

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want to do is I want to modify my reverse file so I'll say sudo nano and then 0168 go into this

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file right here this should be empty what I'll do is I'll paste this in there we go so like I say here

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all this information is going to match my server ipv0.com root.ipv0.com and crucially this serial

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value it has been incremented and it is matching between these two files so again what I'm going

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to do is use my at symbol I'll tab I'll say in I will tab over I'm going to specify my name server

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once again this is going to be my server.ipv0.com. There we go and now what I want to do here is I'm

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going to create what is called a pointer record now I actually could specify the entire ip address

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that I want to be mapping here so because we are in this configuration file 0.168.192

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I can just use the last octet so remember how my ip address is 192.168.0.44 which matches this right

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here in reverse like I say I can actually just leave this off and use the relative value just

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specify the host here okay so if I just say 44 it's going to be resolved to 192.168.0.44 so again

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I'll move in I will say in this time the record is going to be a ptr record remember we talked about

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this in the previous skill the pointer record for the reverse lookup this is what we're doing right

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here now what do I actually want to specify here I want to specify that the reverse lookup

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444 is going to go to my server like I say my server.ipv0.com.com and also if I just save this

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temporarily and go back out if I go back into the ipv0 database one we're matching this address here

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to my server we also created this fictional email server to the address .50 so let's add that one

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into so I will say 50 will be the address I will say in this will be a ptr and this is going to be

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email server and it's part of the ipv0.com domain . if I actually just save this right now and I

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escape what I want to do here is to actually verify that my configuration files are indeed correct

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now we do have a command that we can use to check these configuration files so we do want to be

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remembering this for the purposes of the examination we're going to say named hyphen check zone and then

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what I'm going to do is I'm going to check the actual zone itself which is going to be ipv0.com

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and then I want to match it with the particular configuration file which in this case is this

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one right here so I will say ipv0.com.db if I hit enter it tells me everything is okay and we can

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actually see the serial value which is three has been loaded when we see this output it means that

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the configuration file appears to be correctly configured that's a good start now the next

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thing we want to do is we want to check the reverse zone also so I'll say named check zone as we did

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before and now what I want to do is to use that reverse lookup so I will say 0.168192.naddr.arpa

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and now I want to provide the reverse zone configuration file which is as we know this one

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right here so I'll say 0.168.192.db and if I hit enter again we get the same output everything is

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okay we can see it's been loaded and again we notice here we have parity between these serial

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values of three now what I want to do is I want to make sure that my bind9 server is indeed started

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so I will say sudo service bind9 start there we go and if you want you can restart the service

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and now what I want to be able to do is to test that the resolution here is indeed working so we

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can do this with the dig commands I'll say dig and what I want to do is I want to specify the

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server I want to use so the server is going to be 192.168.0.44 that's the server I want to use

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and now what I want to do is I want to specify the domain I want to query so I apparently created one

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called ipv0.com let's see if this local server has information about this domain that we've just

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created so if I hit enter here indeed we can see information relating to this particular server

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here all this information that we created within our configuration file now we also if you recall

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created particular records with respect to our server now remember if we go into our configuration

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files we can see here we actually have records for my server dot ipv0.com as well as email server

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let's see if those are actually resolving also so I will say dig and I'll query my local DNS of 192.168.0.44

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of course this will be a different value for you on your machine and now what I want to do is I'm

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going to query my server dot ipv0.com check this out we can actually see here we have the a record

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which correlates this particular value to this particular IP address we see the answer section

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we see the authority section the name server and if I add a up and I change this to I believe it was

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called email server and to enter now here we can see the email server is actually correlating via

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the a record to this particular IP address which we specified so this is really quite cool one thing

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I will also add is that we can also add additional record remember we had things like the mx record

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or the cname record we can also add them into so if I go into sudo nano and I go into my ipv0.com.db

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what I can do here is add additional records and one thing I should actually add here is that noting

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that the semicolon terminates the end of a line we can actually use these to invoke particular

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comments to make our configuration file look a little bit neater so say for example after this

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semicolon I could just say my server and then I can do a semicolon here and I'll just say my a records

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and now I can do a semicolon and I'll just say my cname records I can just do in brackets aliases

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and what I could specify here is just some nice shorthand aliases for my lookups I could just

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maybe use the word mail I'll say in I'll make this a cname type record and what do I want to make that

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an alias for I'll make an alias for email server dot ipv0.com remember in the dot on the very end

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and because I've made a configuration change let me go up to my serial value I will increment that

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to four save you exit let me just go back into my reverse I'll just match that up with four as well

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also save you exit I will restart my server let me check my configuration file is a okay it appears

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everything is working fine so now I could say nslookup mail dot ipv0.com and I'll use my local

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server of 192 1680.44 if I hit enter check this out we can actually see here based on the record

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we specified we actually have a mapping between mail dot ipv0.com to the canonical name email

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server dot ipv0.com and we actually get such information right here the 192 1680.50 ip address

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that we had actually linked with the email server within our records what we could also do is we

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could say nslookup we can look up the ip address 192 1680.50 and we will use our local server 192

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1680.44 if I hit enter we can actually see here we can successfully resolve this ip address to

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this particular domain information that we had specified similarly we can look up 192 1680.44

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again using our local dns server here and to enter and we can also resolve that information too so as

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we can see here there are a few different moving parts with respect to getting our dns zone configuration

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setup we have to specify our forward lookups our reverse lookups we can also add in things such

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as canonical names as well as things we did not even touch such as mx records but for the purposes

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of the examination those are the main key concepts that we have to understand when creating our

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configuration files okay docks I hope this has been informative for you and I'd like to thank you for viewing