troubleshooting Question

NDR 554 5.7.1 - Emails cant be sent - Exchange 2010

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fingwong asked on
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Hi All

I'm just looking for validation here more than anything else.

I have recently moved offices and as part of that we started using a new ISP, who gave us a new range of Public IP's.  External DNS has been updated and my Hub Transport server is receiving emails fine internally and externally.

When however we send them externally I get the above NDR.  We use Maildefender as a smart host and so I'm wondering if its just a case that they are blocking the emails based on the fact that they don't have details of our new Public IP address?

Or is there anything else that I need to check before going to them?

I will post the NDR in the next message for people to cast judgement.

Thanks

Fingwon
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