Score:0

Allowing a single user or domain to relay through Postfix

cn flag

I'm running Postfix on a RHEL7 server. I've started to use a new iPhone to send email, and I'm seeing this in mail.log:

Oct 30 20:15:56 kyushu2 postfix/smtpd[31145]: warning: hostname ue.tmodns.net does not resolve to address 172.58.200.63
Oct 30 20:15:56 kyushu2 postfix/smtpd[31145]: connect from unknown[172.58.200.63]
Oct 30 20:15:56 kyushu2 postfix/smtpd[31145]: NOQUEUE: reject: RCPT from unknown[172.58.200.63]: 454 4.7.1 <[email protected]>: Relay access denied; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<smtpclient.apple>

My assumption is that Postfix sees me as trying to use timboyer.org as an open relay. I don't particularly want to allow all iPhone users to use my mail server as a relay. Is there a way to allow just @timboyer.org to relay?

Thanks,

Tim

in flag
Don't. It is only a matter of time until you have spammers trying to use your open relay to send email that seem to originate from your domain. Fix the real issue which is that you should authenticate, and relay should be allowed after authentication.
Paul avatar
cn flag
Please post the output of `postconf -n`.
Score:1
cn flag

NiKiZe, your answer is absolutely correct. I spent Sunday reading and was going to come back on with a 'never mind!' - I'm working on implementing SASL right now.

http://www.postfix.org/SASL_README.html#testing_saslauthd

Thanks very much for the pointer, and yeah, some spammer would have figured out the open relay thing eventually. :)

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.