One of my clients was having a problem sending mail to one domain.
I've been banging my head on this for a couple hours. Originally it was a dns issue. I resolved that, but now I'm not really sure what it is. I think it's a postfix issue.
here is the error message we get
Last Error: 450 4.7.1 <firstname.lastname@example.org>: Recipient address rejected: SPF-Result=ceelaw1.ceelaw.com.au: 'SERVFAIL' error on DNS 'SPF' lookup of 'ceelaw1.ceelaw.com.au'
ceelaw1.ceelaw.com.au resolves correctly.
here is our spf record: v=spf1 ip4:220.127.116.11 include:ceelaw1.ceelaw.com.au ~all
The only thing I can think of is that the reverse lookup on 18.104.22.168 is not ceelaw1.ceelaw.com.au, but it's 22.214.171.124.static.exetel.com.au
Hoping someone could help.