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What does the "outer cloud" see as the IP address of a mail server refernced to by NAT?

The serial0 address for my router is xxx.xxx.xxx.30. I have a mail and web server set up behind the router with an address of xxx.xxx.xxx.26. My URL resolves to the .26 address. When mail is sent from the mail server to the internet, the IP address for the outgoing mail is labeled with the .30 address as the sending IP address. Will this cause problems when sending to mail servers that compare the sending URL (resolved to .26) to the actual sending IP address (showing as .30)? Should the outgoing mail be labeled with the .26 address as the sending IP address?

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Anonymous
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Re: What does the "outer cloud" see as the IP address of a mail

You should have a static NAT translation on the router that converts xxx.xxx.xxx.26 port 25 and 80 to a local LAN IP address. I normally use the extensible servers option in NAT to achieve this.

Yes it can cause problems for outside mail servers that you are sending email to if they do not recognise your sending IP address when they do a DNS lookup on your mail server.

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