>One disadvantage I see to using this kind of lookup for spam filtering
>is that the DNS isn't the sort of thing you really want to be updating
>often, at short notice, and slamming in a spam filter quickly is
>something one sometimes wants to do. If your mail systems are spread
>around a large network with several secondary nameservers, a DNS update
>will take some time to propagate.
Having said that, future versions of DNS server implementation are likely
to include fast incremental updating.
Martyn
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| Martyn Hampson | Tel: 0171 594 6973 |
| Imperial College | Fax: 0171 594 6958 |
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