RDNS of MX Record sees IP of router

[ekwstats]

After switching to a new ISP I am getting RDNS rejects when trying to send to mail servers that check RDNS. My mail server mx record mail.mailserver.com is set to the private routable address 1.2.3.4 and when you do a RDNS check at DNSStuff.com it resolves correctly. The problem is that when a receiving mail server looks at the from email header info it sees the mail server name of mail.myserver.com at IP 5.5.5.5 (IP of my external/serial router port) so the RDNS check fails. I had my ISP put in another PTR for the 5.5.5.5 to also point to mail.mailserver.com, but I wanted to make sure I wasn't creating a mess by having two different IPs with a PTR to the same domain name.
I am learning about DNS on the fly because my consultant and I parted ways midinstall so any help would be appreciated!

Thanks!

 

[lgarner]

Have them remove the RDNS for 1.2.3.4. It looks like your translating the address so the world isn't seeing your "private routable" address.

 

[ekwstats]

Makes sense. It just takes so long to the RDNS addresses in there that I wanted to make sure that was right before I have them remove it.
Thanks!