Zimbra itself has no A / MX record for their mail servers
Installed Zimbra OSE a week or so ago and am quite impressed. Good work Zimbra team.
Decided to sign up to the wiki (have a few discoveries and solutions to share) and the forum. So why didn't my confirmation email come through?
I would really like to keep the postfix option 'reject_unknown_sender_domain' enabled - it is very effective in the fight against spam, yet Zimbra's own mail domain, at least 'www-prod-3.zimbra.com' has neither an A or MX record! Seems strange for a company where this is their business.
May 26 20:50:32 mail postfix/smtpd: connect from mta02.zimbra.com[18.104.22.168]
May 26 20:50:32 mail postfix/smtpd: NOQUEUE: reject: RCPT from mta02.zimbra.com[22.214.171.124]: 450 4.1.8 <email@example.com>: Sender address rejected: Domain not found; from=<firstname.lastname@example.org> to=<email@example.com> proto=ESMTP helo=<mta02.zimbra.com>
May 26 20:50:33 mail postfix/smtpd: disconnect from mta02.zimbra.com[126.96.36.199]
So, in short, don't tick the 'Sender's domain (reject_unknown_sender_domain)' box under 'DNS Checks' in 'Global Settings -> MTA', otherwise you won't get any email from Zimbra!
; <<>> DiG 9.6.0-APPLE-P2 <<>> any www-prod-3.zimbra.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 61626
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;www-prod-3.zimbra.com. IN ANY
;; AUTHORITY SECTION:
zimbra.com. 600 IN SOA sc9-ext-dns-1.vmware.com. hostmaster.vmware.com. 2010051301 3600 900 604800 600
;; Query time: 41 msec
;; SERVER: 10.1.1.1#53(10.1.1.1)
;; WHEN: Wed May 26 21:15:30 2010
;; MSG SIZE rcvd: 107