Outbound IP different from static IP

We have the single static IP option.

We recently started having a problem where outgoing mail is always rejected by the recipient server. While investigating the cause, I made the discovery that our outbound IP address as seen by the peer computer is different from our static IP address. This was seen by the rejection letter, and confirmed by browsing to whatismyip.com.

The address mangling causes us to be rejected on the basis that "if this is a Comcast IP address, you must send mail through the Comcast SMTP server." Well, that is not an option either, since we do not have a Comcast email address nor do we have Comcast hosting our domain email.

What causes the address to be NAT'd for outbound connections, and how can I turn that off?

Responses

Comcast_JamesC

Official Employee

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34 Messages

2 years ago

Greetings, @WendyB! Thanks so much for taking a moment out of your busy day to leave a post on our community forum. I'm sorry to hear you're having issues with your outbound IP address, but you have definitely come to the right place for assistance.

You mentioned this only started happening recently. As far as you can tell, did your outbound mail previously originate from your static IP address, only to change to this new one, or was this just happening without errors up to this point? Has there been any change to your service, software, or equipment, prior to this occurring?

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WendyB

New Contributor

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4 Messages

2 years ago

I can't say for sure that the static IP address used to be seen as the outside source, but there were no internal changes before this happened. It is possible that Spamhaus, among others, have recently implemented new restrictions on who can relay mail. But unfortunately, that still puts us in a bind. Certainly, having our static IP address as the source should go a long way towards improving our server's "reputation" among recipients since we at least have RDNS in place.

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CC_Valerie

Recognized Contributor

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26 Messages

Thank you for reaching back out to us, @WendyB, and for sharing that information with us. Are all outgoing mail rejected or is it only occurring with specific email domains?

I no longer work for Comcast.

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2 years ago

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WendyB

New Contributor

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4 Messages

Specific domains. The messages that were brought to my attention were rejected by Yahoo. The address that the receiving system saw *IS* listed in Spamhaus's problem IP addresses, which is why they told Yahoo to reject it. I confirmed with a query on their page. And the reason specified is that it's a shared Comcast address, therefore it's not trustworthy.

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2 years ago

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CC_Kimberly

Contributor

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18 Messages

Thank you so much for all your time and patience.

Please send us a direct message with your full name, business name, full address, and phone number. By clicking the "message" icon in the upper right page of our forum page. Once you click on that, input our shared handle (Comcast Business) to send us a private message.
• Click "Sign In" if necessary
• Click the "Direct Message" icon in the top right corner
• Click the "New message" (pencil and paper) icon
• The "To:" line prompts you to "Type the name of a person". Instead, type "Comcast Business" there
• - As you are typing a drop-down list appears. Select "Comcast Business" from that list
• - An "Comcast Business" graphic replaces the "To:" line
• Type your message in the text area near the bottom of the window
• Press Enter to send it

I no longer work for Comcast.

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2 years ago

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M

mjstonesr

New Contributor

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4 Messages

11 months ago

I have same issue. The Gateway IP is the public IP that all traffic coming from my network shows, instead of my assigned static IP. How to configure the Comcast gateway to remedy this?

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Comcast_PeterB

Official Employee

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23 Messages

Hello and thank you for your post @mjstonesr sounds like we need to make sure your reverse DNS is set up correctly. Do you know if your plan comes with a configured static IP or do you pay for one?

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11 months ago

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