#### Managing Reverse DNS (Adding PTR Records)

PTR (pointer) records are the reverse of A records: whereas the latter maps names to addresses, PTR addresses map addresses to names. PTR records are not stored in the main zone database for mydomain.com, but in another database which covers reverse lookups. There is a special domain set aside for reverse lookups: `in-addr.arpa`. PTR records reference addresses with respect to this zone. In practice, this means that when creating a PTR record, the numerical address is reversed and followed by "in-addr.arpa." So the PTR record for the IP address `192.168.40.34` would refer to it as `34.40.168.192.in-addr.arpa`.

Below is the example of the reverse zone:

40.168.192.in-addr.arpa. IN SOA ns1.mydomain.com. root.mydomain.com. (

2004031101 ; Serial

10800 ; Refresh

3600 ; Retry

3600000 ; Expire

86400 ) ; Minimum

;

34 IN PTR first.mydomain.com.

The reverse DNS zone appears as soon as the A record is added to the direct zone. The single reverse zone is created for IP addresses from the single subnet. For example, if you add an A record that maps the domain `third.mydomain.com` to the 192.168.40.55 address, the corresponding PTR record will be added to the reverse zone described in our example:

`55 IN PTR third.mydomain.com`

To edit a reverse DNS zone:

1. Select Service Director - Domain Manager - Domains.The list of all domains appears on the screen.
2. Click the Reverse DNS tab. The list of all reverse DNS zones appears on the screen.

   Note: Using the Parallels Business Automation - Standard web-based interface, you can manage only the reverse zones created for IP addresses that stored in the Parallels Business Automation - Standard database. For external IP addresses reverse zones are not created.

3. Select the reverse zone. The list of all records (excluding SOA) that contain in the reverse zone file appears on the screen.
4. Click the New Record button.
5. Fill the form that appears:
   1. Type the record name into the Name field: in this case it should be the last number of the IP address (for example, 45). This is the question of the query.
   2. Into the TTL field you can type in seconds how long other name servers should cache, or save, this record (TTL is short for time-to-live). For example, the 86400 value corresponds to one day.

      Note: The minimal default TTL for all the resource records containing in the zone file is indicated in the Domain Manager > Setup > General. And this default TTL can be re-defined for every record containing in the zone file. Thus, if you leave the TTL field empty, then the default minimal TTL will be applied to this record.

   3. Select the type of the resource record (NS, CNANE, or PTR) from the Type drop-down menu. For more information on resource records, please refer to the DNS documentation, for example, you can look at the Web.
   4. In the Value field you should indicate the answer to the query. Type the rest of resource record here.
   5. You can enter a free form comment into the Comment field.
6. Click the Save button.

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