In this scenario, we decided that the 1.1.10.in-addr.arpa primary domain file will be maintained on child server OTHERHOST. To do this, we need to delegate the reverse mapping file to the child server also. The way to do this is to subnet the 1.1.10.in-addr.arpa file. First we explain the steps to do this on the parent server and give a further explanation about why we have to do this.
Complete the following steps on the parent server AS1:
1. Right click on the label Primary Domains under the title of DNS
Server-as1.mycompany.com.
2. Click on New Primary Domain. See Figure 96.
Figure 96. Creating the Two-Byte Primary Domain FIle 1.10.in-addr.arpa on AS1
Under the General Tab’s Domain Name field, type in 1.10.in-addr.arpa. and leave the Create and delete reverse mappings by default check box
unchecked. See Figure 97.
It is important to notice that in this section, we configure a 2-byte in-addr arpa file, 1.10.in-addr.arpa on AS1. This is a different primary domain file than the
3-byte in-addr.arpa file, 1.1.10.in-addr.arpa file that is created on the child
server OTHERHOST. Right now, this may be a little confusing so just be aware that 1.10.in-addr.arpa is a different primary domain from the 1.1.10.in-addr.arpa primary domain. This is similar in concept to saying that the mycompany.com
primary domain is a different primary domain from the
OTHERDOMAIN.mycompany.com that we configure later on in the child server
OTHERHOST.
Figure 97. Entering the Domain Name when Creating the 1.10.in-addr.arpa Primary Domain File
3. Click OK. The new primary domain file of 1.10.in-addr.arpa should be displayed in the list of primary domain files.
4. Right click the 1.10.in-addr.arpa primary domain file. 5. Click Properties.
6. Click the Secondary Name Server Tab. 7. Click Add.
8. In the domain name field, enter the domain name of the three byte
in-addr.arpa domain: 1.1.10.in-addr.arpa. (do not forget the trailing period after com). See Figure 98.
Figure 98. Entering 1.1.10.in-addra.arpa’s Domain Name for Secondary Name Server in 1.10.in-addr.arpa File
9. Click OK.
10.In the host field, enter OTHERHOST.OTHERDOMAIN.mycompany.com. (Do not
forget the trailing dot after com.) 11.Click OK.
14.Click Enable to enable this primary domain.
If a client sends a reverse lookup query to the parent server AS1 (for example, the client knows the IP address 10.1.1.9 and is querying AS1 for corresponding host name), the name server on AS1 uses the NS record we just created within 1.10.in-addr.arpa to find out that the authority for the 1.1.10.in-addr.arpa resides on the child server OTHERHOST. AS1 either tells the client to go query the OTHERHOST
name server for the answer or AS1 will query the OTHERHOST DNS server on the client’s behalf.
Continuing on...:
We now need to add the OTHERSERVER host to the 69.5.10.in-addr.arpa primary domain file on the parent server AS1. Although the OTHERSERVER host is in the
OTHERDOMAIN subdomain that the child server OTHERHOST is authoritative for,
the parent server AS1 is authoritative for the entire 69.5.10.in-addr.arpa primary domain file. Because OTHERSERVER has an IP address in the 10.5.69.192 network, this host must be added into the 69.5.10.in-addr.arpa file on the parent server AS1. See Figure 83 on page 89 to review the network diagram and IP addresses. 15.Right click the 69.5.10.in-addr.arpa primary domain file.
16.Select New Host. 17.Click Add.
18.Enter host name: OTHERSERVER.OTHERDOMAIN.mycompany.com. (do not
forget the trailing period after com).
19.In the same window, enter the IP address of 10.5.69.207. 20.Click OK.
21.Click OK.
22.Close the DNS server configuration window to save the configuration on the parent server, AS1.
Figure 99 shows the contents of the 2-byte 1.10.in-addr.arpa primary domain file on AS1. This file is in the IFS directory /QIBM/UserData/OS400/DNS. Unlike the 3-byte in-addr.arpa files, this file does not contain any PTR records. The purpose of this file is to contain an NS record that points to the child name server
OTHERHOST. The child name server OTHERHOST contains the 3-byte
1.1.10.in-addr.arpa primary domain file for the network 10.1.1.0 and that is the At this point, you may be wondering "what did we just do?" We created a new primary domain file but we did not add any hosts to it. If we click on the 1.10.in-addr.arpa file, we see that it is empty of any records. In steps 5 through 12, we created an NS record specifying the child server OTHERHOST for the 1.1.10.in-addr.arpa primary domain file. Essentially this is telling the parent server AS1 that the primary reverse mapping file of 1.1.10.in-addr.arpa exists on the child server OTHERHOST. You can think of the NS record in this case as a pointer to help the parent server, AS1, find its way down the DNS name space tree to the server that is authoritative for the 1.1.10.in-addr.arpa domain, which is the child server OTHERHOST. In conclusion, we just delegated the
1.1.10.in-addr.arpa domain to the child name server OTHERHOST. Tip
Figure 99. Contents of 1.10.in-addr.arpa Domain File on AS1
Summary of Method 2 Configuration
The configuration of the delegation of domain OTHERDOMAIN and the
1.1.10.in-addr.arpa domain on the parent server AS1 is complete. We still need to perform additional configuration changes on the child server,OTHERHOST, which we cover in the next section. Figure 100 shows the list of primary domain files (in the left column of the Operations Navigator display) residing on AS1 parent server. Notice the 1.10.in-addr.arpa primary domain. Figure 100 also shows the contents of the mycompany.com primary domain file (in the right column of the Operations Navigator display).
Figure 100. Contents of AS1’s mycompany.com Primary Domain File