Versions Compared

Old Version 24

changes.mady.by.user ASF Infrabot

Saved on

compared with

New Version 25

changes.mady.by.user ASF Infrabot

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.
Comment: [Original edit by JohnHardin] Explain risk of forwarding DNS to busy ISP

...

No Format
options {
...
  forward only;
  forwarders {
    IP_DNS_1;
    IP_DNS_2;
  };
...
};

However, if you have a large ISP who has many customers who are also doing DNSBL lookups, and the ISP has not registered with the DNSBL provider as a paid client, the aggregate traffic from the ISP's nameservers may exceed the free usage limits imposed by the DNSBL provider and lookups may start returning invalid results. This could lead to large numbers of incorrectly-classified messages.

If you have a large ISP it is recommended you not forward mail-related DNS traffic through their DNS servers (though non-mail DNS traffic from your site shouldn't have problems.)