On 12/15/2016 8:56 AM, L.P.H. van Belle wrote: > Hello, > > > > I couldnt find this on the internet and is was thinking, the postfix > list wil know this. > > Customer send email which are rejected by my server. I thinks that > is correctly rejected. > > > > Now i digged into this and i found the following but i dont know if > this is allowed by RFC. > > To me this should not be done but if someone can conform this, that > would make me happy. > > > > Log part > > Dec 15 14:22:23 mailrelay postfix/smtpd[3361]: NOQUEUE: reject: RCPT > from unknown[1.2.3.4]: 554 5.7.1 ,<host.domain.tld>: Helo command > rejected: Host not found; from=<XXXX@DOMAIN2.TLD2> > to=<mym...@myoffice.tld> proto=ESMTP helo=<host.domain.tld > > > >
The message was rejected because the HELO name had no A nor MX record *at that time*. Hosts are allowed to have multiple A records, but the client may be labeled as "unknown" because postfix won't walk through all possible hostname/IP combinations looking for a match. Many legit hosts will fail reject_unknown_helo_hostname. Use with caution. -- Noel Jones
