There is one ISP that is rejecting mail from my mail server with the following error: Code: 451 4.1.8 Possibly forged hostname for 205.209.51.116 My domain is mercedesshop.com. Is there a problem with my mail server or is the issue with that ISP? This is the definition I found for error 451 4.1.8: "This means that it was able to resolve the IP address, but it doesn't resolve to a hostname that matches both forward and reverse lookups." Please note that all of my incoming mail is routed through a proxy mail server to filter spam and viruses. I would not think that would make any difference for SMTP.
Since my servername is mbshop2.mercedesshop.com Would it help if I added an A record for mbshop2? I am not using mbshop2 as a hostname for any of my webs.
Success! Adding an A record for mbshop2 seems to have fixed the problem with the one ISP that was refusing email from my server. Now on to the next problem... I have another customer who is not getting emails from us. This one has a US Army email address. Whenever my mail server sends to him the connection times out. This one may be tougher to solve because there's no error code.
