BlackListed IP

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Joined: Sat Oct 15, 2022 7:58 am

BlackListed IP

Post by Sharkee12 »



I'm a residential end user and don't run mail servers here. I had an email bounce and it didn't make sense why, so that's why I looked into this.

I went to WhatsMyIPAddress and ran a Blacklist check. All the blacklists had a green checkmark except two: and

I then went to, did not yet create an account, but this is what came up there:

Summary information for
Note: Times shown are for the latest entry only!
Found 2 network entries and 0 host/domain entries.

Usage classification (only important if you run your own mailserver.)
... *snip*
Current Listings (active)
Historical Listings (inactive)
Current Listing with an active exception
Current Listing however, listings of these types can help mail delivery rather than cause blocking.

First question: is that a cause for concern? And then, will that have any effect on sending and receiving email?

Here's the bounced email. It appears either AT&T or Yahoo (AT&T cobranded with Yahoo to do my sbcglobal email) uses ProofPoint, Inc., or at least that's my guess about what pphosted and ppops are.

Mail Delivery Subsystem <[email protected]>
Sat, Oct 15 at 8:35 AM
The original message was received at Sat, 15 Oct 2022 13:30:07 GMT
from []

----- The following addresses had permanent fatal errors -----
<[email protected]>
(reason: 550 5.4.1 Recipient address rejected: Access denied. AS(201806281) [])

----- Transcript of session follows -----
... while talking to
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. AS(201806281) []
550 5.1.1 <[email protected]>... User unknown
<<< 503 5.5.2 Need rcpt command []

Any advice?
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Re: BlackListed IP

Post by Chrispcritters »

The DUL listing and its rolling up with the combined SORBS listing basically means that it's a dynamically assigned IP address on which a mail server should not be running. Since you are not running a mail server from home, you can safely ignore those two listings.

The error message indicates that the email address you are sending to, [email protected], is not a valid email address.
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Re: BlackListed IP

Post by Sharkee12 »

Fantastic. Thanks for your assistance.
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