----- Original Message -----
From: "Roger Moser" <roger_moser_spf(_at_)greenmail(_dot_)ch>
To: <spf-discuss(_at_)v2(_dot_)listbox(_dot_)com>
Sent: Saturday, July 17, 2004 4:02 PM
Subject: Re: PTR lookups in SPF (was: [spf-discuss]SPF is not usable as legal
measure against spammers.)
Andriy G. Tereshchenko wrote:
What is reason to do PTR lookups in SPF ?
I have "v=spf1 ptr:untd.com -all" as a fall-back record for juno.com.
In this way I don't have to guess all the IP addresses they are using to
send mail.
Do you feel yourself safe ?
http://ws.arin.net/cgi-bin/whois.pl ("Juno")
Juno Online
SPRINT-CF34DB (NET-207-52-219-0-1) 207.52.219.0 - 207.52.219.255
SPRINT-CF34DC (NET-207-52-220-0-1) 207.52.220.0 - 207.52.220.255
Juno Online Services
JUNO2 (NET-207-205-100-0-1) 207.205.100.0 - 207.205.100.255
JUNO3 (NET-207-205-110-0-1) 207.205.110.0 - 207.205.110.255
JUNO4 (NET-207-53-99-0-1) 207.53.99.0 - 207.53.99.255
JUNO5 (NET-207-53-52-0-1) 207.53.52.0 - 207.53.55.255
JUNO-1 (NET-64-66-201-0-1) 64.66.201.0 - 64.66.201.255
JUNO-BLK (NET-64-136-0-0-1) 64.136.0.0 - 64.136.63.255
Random sampling:
JUNO4
15.99.53.207.in-addr.arpa.: Server failed
JUNO5
15.52.53.207.in-addr.arpa.: Server failed
JUNO3
100.110.205.207.in-addr.arpa.: Server failed
JUNO2
100.100.205.207.in-addr.arpa.: Server failed
JUNO-1
6.201.66.64.in-addr.arpa name = 64-66-201-6.stkn.mdsg-pacwest.com
JUNO-BLK
123.0.136.64.in-addr.arpa.: Non-existent domain
SPRINT-CF34DB
45.219.52.207.in-addr.arpa.: Non-existent domain
SPRINT-CF34DC
45.220.52.207.in-addr.arpa.: Non-existent domain
Not all IPs assigned to Juno has untd.com PTR data.
Do you still feel yourself safe using PTR records now ?
To keep your SPF information up to date you have to find a way
to use whois or possibly BGP or catch bounces and modify SPF records
PTR does not solve routing problem created with SPF.
FYI, http://rfc.net/rfc822.html
----
6.2.7. EXPLICIT PATH SPECIFICATION
At times, a message originator may wish to indicate the
transmission path that a message should follow. This is
called source routing. [....]
Note: The use of source routing is discouraged. Unless the
sender has special need of path restriction, the choice
of transmission route should be left to the mail transport service.
----
Do we now go back to pre 1982 times ?
--
Andriy G. Tereshchenko
TAG Software
Odessa, Ukraine
http://www.24.odessa.ua