On 4/28/2011 2:56 PM, motty.cruz wrote: > Thanks Raindl, > Problem was fixed; but I don't want to open my spam filter server to > spammers. Do you think that is a DNS configuration issue on our client's > DNS? When I issue the following command on the spam filter server > # nslookup client.ip.address > Server: my.dns.serverip > Address: my.dns.serverip#53 > > Non-authoritative answer: > Client.ip.address.in-addr.arpa name = mail.clientdomain.com. > > Thanks for your help.
For reference, the temp-fail was on reject_unknown_sender_domain not reject_unknown_(reverse_)client that you demonstrated. To be fully complete, you should check your DNS lookup against the "tld.com" you specified not the IP. As noted elsewhere, a real MTA will retry for several days. No panic button needed. Brian > -----Original Message----- > From: owner-postfix-us...@postfix.org > [mailto:owner-postfix-us...@postfix.org] On Behalf Of Reindl Harald > Sent: Thursday, April 28, 2011 11:28 AM > To: postfix-users@postfix.org > Subject: Re: NOQUEUE: reject: RCPT from unknown[xxx.xxx.xxx]: 450 4.1.8 > > > > Am 28.04.2011 20:20, schrieb motty.cruz: >> Hello, >> >> Looks like one of our clients are trying to email us but their emails >> are getting rejected. I'm sorry I will not display customers ip >> >> Apr 28 11:11:12 host postfix/smtpd[48962]: warning: hostname >> mail.tld.com does not resolve to address xxx.xxx.xxx Apr 28 11:11:12 >> host postfix/smtpd[48962]: connect from unknown[xxx.xxx.xxx] Apr 28 >> 11:11:12 host postfix/smtpd[48962]: NOQUEUE: reject: RCPT from >> unknown[xxx.xxx.xxx]: 450 4.1.8 >> <cli...@tld.com>: Sender address rejected: Domain not found; >> from=<client.tld.com> to=<u...@mydomain.com> proto=ESMTP >> helo=<mail.tld.com> > > 450 is a temporary error and the client will combe back or is not > standard-conform > >> Sender address rejected: Domain not found > your dns can not solve the sender-domain maybe a temporary dns-problem > >> reject_unknown_sender_domain > says you want this behavior > >
