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 IN SOA 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 > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop -- The Delivery Experts Laura Atkins Word to the Wise la...@wordtothewise.com Email Delivery Blog: http://wordtothewise.com/blog
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