In this section of the DNS server properties dialog, you specify DNS look up settings for this DNS server:
Use EDNS0
Enable this option to allow larger DNS packets over UDP with DNS servers that support this.
For details on EDNS0 see RFC2671 at http://www.rfc-editor.org/rfc/rfc2671.txt
Ignore host record TTL value
Ignore the TTL value when comparing DNS host records retrieved via DNS lookup to the TTL value configured in the Server set properties dialog / DNS data section.
Perform a DNS lookup to re-check DNS host records every
Re-check frequency.