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From: donovan jeffrey j (donovanbeth.k12.pa.us)
Date: Thu Aug 12 2010 - 13:07:45 CDT
all day long I see tons of reject warnings from different ips sample
reject_warning: RCPT from unknown[126.96.36.199]: 450 Client host rejected: cannot find your hostname, [188.8.131.52];
when I do an nslookup or host that IP it returns a 184.108.40.206.in-addr.arpa domain name pointer sh4.amazingfireman.info
but dig returns nothing so postfix returns a reject warning.
Much of this mail is unwanted , i want to block the majority of these however I do not want to block users that use a colocation site or legit users;
example; i know these people are legit but have no control over their mailserver
reject_warning: RCPT from unknown[220.127.116.11]: 450 Client host rejected: cannot find your hostname, [18.104.22.168]; from=<userdhuy.com>
22.214.171.124.in-addr.arpa name = ip70-106-tcpbbs.net.
dig shows nothing for that ip but they do have an mx record under their domain name dhuy.com
;; ANSWER SECTION:
dhuy.com. 1595 IN MX 10 mail.dhuy.com.
nc1-100:~ drfoo$ host 126.96.36.199
188.8.131.52.in-addr.arpa domain name pointer ip70-106-tcpbbs.net
it goes in a circle.
So in hopes that i can allow them to pass i have added the IP to my smtpd_client_restrictions = permit_mynetworks check_client_access hash:/etc/postfix/access
is that the right approach ?
insight and flames welcome