Sender Maturity after IP change

[ixnay]

Hi guys

So I have a couple of domains that send email to a specific client that uses Cisco Secure Email. I've recently had to change some domains to another server, so the IP changed. Suddenly this client stopped receiving our emails, even if they came from the same domain.

This reputation on this new IP is at GOOD already so I wonder if the IP change impacted on the Sender Maturity feature?

Thanks.

[Dustin Anderson]

You would need to see the receiving logs to be sure, but most of the maturity is on the domain itself, not the IP. Did you update your SPF for the new IP address  etc?

[ixnay]

Yes, absolutely. New IP is part of the SPF, also DKIM and DMARC are correctly configured. Only thing that changed was the IP.

What is even more weird is that if I send emails from domains on the old IP, they get to this client. If I change them tomorrow to the new server with the new IP, they don't get there, even if the emails are accepted by the remote server (xxx.xxx.xxx.iphmx.com 250 ok: Message xxxxx accepted).

Unfortunately this is a very big international client and very hard to get to their IT department. I'm just trying to learn what could be the issue here as we have years of history of mails exchange between these domains, with no issues whatsoever.

[Dustin Anderson]

do you use o365 for your domain? I know they have to add your server to a warming list if it's new, but that is something support does. We had to do it when we added a 3rd server and hence a 3rd IP. 

You said the IP was good, so I'm assuming in Talos. you could also check any blacklist at mxtoolbox.

https://mxtoolbox.com/blacklists.aspx

Other than that without seeing a log on the receiver to know why it's not delivering. You are able to email yourself with the new IP?