DNS Zones Print

  • 5

There are many recommendations for DNS zone settings, Here are mine as follows:

    * SOA record [TTL=14440]
    * PASS SOA REFRESH value OK. Your SOA REFRESH interval is : 4800 seconds. This seems normal (about 3600-7200 seconds is good if not using DNS NOTIFY; RFC1912 2.2 recommends a value between 1200 to 43200 seconds (20 minutes to 12 hours)). This value determines how often secondary/slave nameservers check with the master for updates.
    * PASS SOA RETRY value OK. Your SOA RETRY interval is : 3600 seconds. This seems normal (about 120-7200 seconds is good). The retry value is the amount of time your secondary/slave nameservers will wait to contact the master nameserver again if the last attempt failed.
    * PASS SOA EXPIRE value OK. Your SOA EXPIRE time: 1209600 seconds. This seems normal (about 1209600 to 2419200 seconds (2-4 weeks) is good). RFC1912 suggests 2-4 weeks. This is how long a secondary/slave nameserver will wait before considering its DNS data stale if it can't reach the primary nameserver.
    * PASS SOA MINIMUM TTL value OK. Your SOA MINIMUM TTL is: 6000 seconds. This seems normal (about 3,600 to 86400 seconds or 1-24 hours is good). RFC2308 suggests a value of 1-3 hours. This value used to determine the default (technically, minimum) TTL (time-to-live) for DNS entries, but now is used for negative caching.

    The SOA record is:
    Primary nameserver: ns1.codwebhosting.com
    Hostmaster E-mail address: difiglia28.comcast.net
    Serial #: 2008123104
    Refresh: 4800
    Retry: 3600
    Expire: 1209600   2 weeks
    Default TTL: 6000

To modify your zones quickly, SSH into your system:
Now lets say you want to update the 3600000 TTL for SOA --- as shown in DNS stuff...
from cli (command line interface) run:

    /usr/bin/replace '3600000' '1209600' -- /var/named/*.db

Now do the same for the other values changing them accordingly!

Restart BIND and you are done!

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