Hi Laura,
I think we have to disagree here. The PTR naming is set via SendGrid.
It doesn't NEED to be the same as the A record. This is for those MTA's
that do forward/reverse matching, which isn't always successful.
Yes, doing that for a IPv6 email address to satisfy Google, go ahead.
But nothing wrong with sending an email from a PTR with a name, that
doens't have the FQDN forward/reverse matched.
As long as there is a URL associated with the domain name.
eg. http://mileageplus.com (Redirect to UA site URL)
Perfect forward/reverse FQDN matching is still a little aggressive IMHO,
and especially problematic. Some people think they need 20 PTR records,
one for each A record.. (No, that is worse)
Postfix does allow forward/reverse checking, I would NOT enable that for
the IPv4 space (yet)
On 2023-05-09 10:22, Laura Atkins via mailop wrote:
That’s a Sendgrid IP, they likely told UA to put in a DNS record, but UA
never did. ¯\_(ツ)_/¯ n
On 9 May 2023, at 18:01, Stephen Frost via mailop <mailop@mailop.org>
wrote:
Greetings,
I'm getting some inbound email attempts that I believe are legitimate
from United Airlines that are being rejected due to:
May 9 12:55:38 tamriel postfix/smtpd[1221960]: warning: hostname
o1.email.smallbusiness.mileageplus.com does not resolve to address
50.31.61.242
Tracking this back, near as I can tell, postfix is correct here in that
50.31.61.242 / 242.61.31.50.in-addr.arpa resolves to
o1.email.smallbusiness.mileageplus.com but
o1.email.smallbusiness.mileageplus.com doesn't seem to actually exist:
dig o1.email.smallbusiness.mileageplus.com a
;o1.email.smallbusiness.mileageplus.com.IN A
;; AUTHORITY SECTION:
smallbusiness.mileageplus.com. 600 INSOA
vndcdf-fs0000-gma3-vip.ual.com. ualipconfig.united.com. 40 10800 3600
2592000 600
Hopefully someone on here is from UA or knows how to get in touch with
someone there who could like into fixing that.
Thanks,
Stephen
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