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RE: rr.com and SPF records

2005-03-16 15:46:06
Todd Herr wrote:
So, just so I'm clear on things here...

Would the following be an acceptable SPF record for rr.com?

"v=spf1 ip4:24.30.203.0/24 ip4:24.28.200.0/24 \
        ip4:24.28.204.0/24 ip4:24.30.218.0/24 \
        ip4:24.93.47.0/24 ip4:24.25.9.0/24 \
        ip4:65.24.5.0/24 ip4:24.94.166.0/24 \
        ip4:24.29.109.0/24 ip4:66.75.162.0/24 \
        ip4:24.24.2.0/24 ip4:65.32.5.0/24 +mx ~all"

Acceptable, that is, from the standpoint of fewer than 10 methods
and guarding against the forged @rr.com sender that Radu spoke of
upthread?

From _that_ standpoint: yes.

But does the record authorize _more_ IP addresses for sending mail from
rr.com than necessary?  In other words: is it too broad?

  $ for a in $(
  >>     dig +sho rr.com MX | cut -d' ' -f2
  >> ); do
  >>     dig +sho $a A
  >> done | sort | uniq | wc -l
  36

As far as I can see, the above record authorizes 12*254 + 36 = 3084 IP
addresses to send mail from the domain rr.com.  Is this appropriate?


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