Do some spammers ignore MX ptrs?

[BB]

1. Its hosted by the ISP and doesn't cost anything
2. Its a great filter rule

On 4/27/06, cobalt-users1 at fishnet.co.uk <cobalt-users1 at fishnet.co.uk> wrote:
>
> On 27 Apr 2006 at 8:30, Michael Masse wrote:
>
> > I'm offloading just Mailscanner services from an overloaded email store
> > machine to a new machine and am doing so by pointing the MX record for
> > the domain to the new machine.   The A ptr still points to the old
> > system so that none of the other services this machine provides get
> > interupted.     All legitimate email and most spam is going to the new
> > system like it's supposed to and it then gets relayed to the old store
> > machine, but I'm noticing quite a bit of spam is still being sent
> > directly to the old system.     Does some spam software ignore the MX
> > ptr and go to the A ptr instead, or is this more likely to be a DNS
> > cache issue on the sending systems that will hopefully clear itself out
> > over a few days?
>
> Hi,
>
> Its not just spammers but bad programmers as well.  Several years ago I
> noticed that behaviour
> in some Windows email systems.  It may have been fixed now.
>
> I never put an A record in for domain unless there is a very good reason.
>
> Ian
> --
> -------------------------------------------------------------
> Ian Gibbons
> Fish.Net Ltd                     Providing Internet Solutions
> http://www.fishnet.co.uk      e-mail IanGibbons at fishnet.co.uk
> Tel +44 (0)1457 819600                 Fax +44 (0)1457 819602
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