North American Network Operators Group
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Re: Barracuda Networks Spam Firewall

  • From: Eric A. Hall
  • Date: Tue May 18 20:05:58 2004 
On 5/18/2004 6:44 PM, Per Gregers Bilse wrote:

> For a long time since then, backup MXs have been seen as a kind of 
> value-added courtesy service; they serve no really useful purpose

well, they're handy for centralizing filters against multiple domains, if
you're willing to put your various primaries at the mercy of the filter
service, and if the filter knows your valid recipients. what with
ldap-smart servers and fancy routing, this isn't even hard anymore.

but general "backup" MX is long-time dead. first the spammers killed our
outbound flexibility by forcing everybody to close their relays, and then
they killed our inbound flexibility by forcing everybody to close their
generic backup MX paths. that cracking sound is stress fractures as the
network gets more rigid.

-- 
Eric A. Hall                                        http://www.ehsco.com/
Internet Core Protocols          http://www.oreilly.com/catalog/coreprot/