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IP and DNS Change Question regarding Exchange Email

Last night around 5pm we changed our outside facing IP Address to our new fiber provider. I had my DNS host (my old ISP) change my DNS Records to point mail.domain.com owa.domain.com and ftp.domain.com all to our new IP.
whatsmydns.net shows the IP has propagated out around most of the world by now but I am still having an issue-
We seem to be receiving email just fine (I have a hosted Spam/Email archive solution and I updated my IP with them as well, and connectivity between us is fine).
However, it seems a lot of emails we are sending aren't reaching there destination. I can email my yahoo, my gmail, but not an Office365 Hosted Email address for example.
Did I perhaps miss a change I needed to make on my Exchange 2003 server, or my DNS Server internally? As expected, it's not a good situation when some email goes out, and some doesn't. Especially when for example my Office 365 address I sent too didn't even generate a bounce (at least not yet).

Thanks!
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Imtiaz Hasham
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Where would I check my outbound server address?
Our Firewall has one IP address, and my email flows through to my Exchange Box based on Firewall Rules using the Port #'s, and locked down to the IP Addresses of MXLogic (McAfee, my outside hosted spam/archiving solution)
Wait for next 72 hours and then check again. it takes minimum 3 days for any DNS change to replicate Globally.
Josh: Check the outbound server address on your exchange server.  They are called SMTP Relays.

Amit: unless you have a very high TTL (which is not recommended), DNS changes are within 20 mins and NS changes are within 24 hours.
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ihasham-
I checked my SMTP Relays and there are none. (under Admin Groups, First Admin Group, Servers, EMAIL SERVER, Protocols, SMTP, Default SMTP Virtual Server, Properties, Access, Relay Tab.)
Shows no IP's listed (this was not changed last night, has always been like this). Checkbox for allow All computers which authenticate successfully to relay.
Email flowing out was working fine up until this DNS Change.
The fact that we are receiving emails from companies we can't send to is what is confusing me, and making me think that either their side is thinking I am sending email from an IP I am not still, or something like that.

Would appreciate any other idea's or things I should check.
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Also, I just noticed I can see many emails now stuck in my Outgoing Queue on the Exchange Box.
How is your outbound email set to deliver email??

Are you using a smarthost? Have you updated your IP details with them if you are. To check this go to Internet Mail Connector and see how it sends email.

 
IP Addresses of MXLogic (McAfee, my outside hosted spam/archiving solution)

Have you updated any NAT policies in your firewall for outbound email delivery?

Can your exchange box telnet to an email server on the internet via port 25?
Receiving and seding emails is two different things...

Your new IP could've been blacklisted due to spam etc.  I would recommend using a host such as authsmtp.com to get your emails delivered and they have their setup config on it.

We also run a service such as authsmtp but it's used for our clients only, not for anyone else hence my recommendation of using authsmtp.

And yes, I would check outbound policies on the firewall as suggested, in case you've got a block there.

If you want to test telnet outbound, there are many available servers, just check anyone's DNS records, find their MX record and telnet on port 25
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My comment was what I did to fix the problem.