email header claims a different ip than my mail server

[wfbtr]

hello-
when I send mail from my exchange the source IP in the header is a different IP than my mail server's public IP.
I can ping my mail server's DNS name and also public IP address and get a proper response. So I'm wondering where the source IP address is coming from on the header.

thanks in advance.

 

[wfbtr]

anyone know how to tell where my header IP is coming from?

 

[llevon]

Do you use any Mail spam or AV services like message labs?
These can change the headers.

Also if you supply the IP address in question we can lookup who it belongs too.

The link below is a useful starting point in identifying the owner of the IP address.

http://www.demon.net/external/

llevon

 

[wfbtr]

thanks llevon-
i don't use any spam or mail services other than norton.
here's the ip:
208.251.110.195

it shows the owner as UUnet.
Isn't UUnet partners with MCI? MCI is my ISP.

 

[llevon]

When sending email does your Exchange server use DNS to resolve and send the email directly or do you send the email via a smtp smarthost e.g. your firewall or your ISP?

llevon

 

[PScottC]

Very often your firewall will use your NAT IP for outbound traffic regardless of the traffic type. You probably have a static NAT configured to deal with inbound SMTP traffic only. You will need another rule to static NAT the outbound traffic also.

PSC

Governments and corporations need people like you and me. We are samurai. The keyboard cowboys. And all those other people out there who have no idea what's going on are the cattle. Mooo! --Mr. The Plague, from the movie "Hackers

 

[wfbtr]

i have a managed router by mci and there's no firewall. i'm not exactly sure what a smarthost is or how to tell if we are using one.
thanks.