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Thursday, September 3rd, 2026 1:11 AM

Reverse DNS for my IP address is returning SERVFAIL

The reverse DNS for my IP address (in the 71.238.123.0/24 block) is returning SERVFAIL. This is not a request for a custom PTR record, I understand those aren't offered on residential accounts. The issue is that the existing reverse zone is answering inconsistently.

`dig -x <ipaddress> @8.8.8.8` returns status: SERVFAIL, while the same command against @1.1.1.1 returns status: NOERROR. Additionally, a network admin at a site I routinely connect to independently also sees status: SERVFAIL from their own resolver. 

This has made fresh ssh connections for work take roughly 30 seconds longer than they should, a problem that only began when I got my new router, so I believe that I'm on a new IP whose reverse zone is broken. 

I'm happy to provide the exact IP address privately.

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Official Employee

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4.3K Messages

2 hours ago

Hey there, @dns_woes, thanks for reaching out through Xfinity Forums regarding your DNS issues. We would be happy to take a look at this issue on our end and help with troubleshooting. Please send us a Direct Message with your full name and your full address. 

 

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