I would suggest trying to contact hostduplex which is the registrant contact for fortifiedserver.net and seeing if it's one of their servers or a cloud server of theirs.
On 11 April 2018 at 17:29, Ross Wheeler <aus...@rossw.net> wrote: > > Gentlemen (and ladies!) - I'm not often stuck with no idea which way to > even begin... but I am this afternoon. > > I've a customer who has been trying to email a supplier of theirs, but the > mail keeps bouncing back. It's not the usual fat-fingered address. When I > started investigating it, I see the recipients email is handled by mx1 and > mx2.fortifiedserver.net > > When I send an email (from a different domain to my customer) to the > recipient I get an immediate bounce that says: > > ----- Transcript of session follows ----- > ... while talking to mx1.fortifiedserver.net.: > >>> RCPT To:<****@******.com.au> > <<< 550 Sorry, we do not accept connections from you. > 550 5.1.1 <****@******.com.au>... User unknown > 451 4.4.1 reply: read error from mx1.fortifiedserver.net. > > > I've checked and my mailservers are not in any blacklist I can find. > I've never been used as a spam relay, or origin of spam, the mail server > reputation on everything I've been able to find is "good". Yes, I have > proper RDNS etc and have had for decades. > > Both http://fortifiedserver.net/ and https://fortifiedserver.net/ are a > waste of time. > whois fortifiedserver.net doesn't return anything useful. > Google isn't returning anything helpful or relevant. > > Anyone got any bright ideas? > > R. > _______________________________________________ > AusNOG mailing list > AusNOG@lists.ausnog.net > http://lists.ausnog.net/mailman/listinfo/ausnog >
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