Re: Cloudflare DNS contact?

 

> On 7 Apr 2026, at 12:08, Betsy Schwartz via NANOG <[email protected]> wrote:
> 
> We're getting reports of users trying to log in or request 2FA emails from
> Cloudflare sites (ex: California DMV) but seeing   errors that our well.com
> domain isn't recognized as valid.  Well.com  has been around since 1993 and
> our primary DNS hasn't changed since perhaps 2012. . Excerpts appended for
> reference.
> 
> I strongly suspect these errors are related to a Cloudflare security check
> for valid email domains. Hoping someone here can validate or disprove
> this.  If it's a Cloudflare issue, any contacts here?
> 
> When I poke at an open cloudflare DNS server and  look up the A for well.com
> I get a disturbing error: :
>         server can't find well.com.well.sf.ca.us:
> 
> well.sf.ca.us is an antique  (but valid) A  record in  the sf.ca.us zone
> and has no business appearing here.  Did something drop a period or  CRLF
> on a list somewhere?

Nslookup is NOT a good diagnostic tool.  Here it presumably tried well.com
then tried well.com.well.sf.ca.us when the first query failed as you have
well.sf.ca.us in the search list.  This is one of the reasons it is not a
good diagnostic tool.  Also different versions of nslookup move onto to
applying the next name in the search list differently.  The only SAFE? way
to do search lists is to ONLY move to the next name on NXDOMAIN (Name Error).
Lots of search list implementations move to the next name in the search list
on SERVFAIL (you can get data from the wrong name used),  NOERROR NODATA (you
end up talking to different domains as IPv4 and IPv6 addresses appear/disappear).

I would suggest that you use a diagnostic tool like 'dig' which doesn’t do search
lists unless explicitly requested.

Additionally if you want help, show everything you are doing.  People then have
a better chance of find errors in your testing methodology.

> When I query AWS and Google DNS servers,  our DNS  looks correct and
> unchanged
> Thank you very much for any pointers!
> 
> Betsy
> 
> --
> Correct info:
>> set type=any
>> well.com
> Server:         8.8.8.8
> Address:        8.8.8.8#53
> Non-authoritative answer:
> Name:   well.com
> Address: 23.22.72.90
> well.com        nameserver = ns-1783.awsdns-30.co.uk.
> well.com        nameserver = ns-1103.awsdns-09.org.
> well.com        nameserver = ns-805.awsdns-36.net.
> well.com        nameserver = ns-459.awsdns-57.com.
> well.com
>        origin = ns-1103.awsdns-09.org
>        mail addr = awsdns-hostmaster.amazon.com
> <snip>
> well.com        mail exchanger = 15 xmx.well.com.
> <snip>
> --
> whois well.com
> [Querying whois.verisign-grs.com]
>   Domain Name: WELL.COM
>   Registry Domain ID: 4562093_DOMAIN_COM-VRSN
>   Registrar WHOIS Server: whois.enom.com
>   Registrar URL: http://www.enomdomains.com
>   Updated Date: 2020-01-24T18:46:10Z
>   Creation Date: 1993-01-25T05:00:00Z
>   Registry Expiry Date: 2029-01-26T05:00:00Z
>  <snip>
>   Name Server: NS-1103.AWSDNS-09.ORG
>   Name Server: NS-1783.AWSDNS-30.CO.UK
>   Name Server: NS-459.AWSDNS-57.COM
>   Name Server: NS-805.AWSDNS-36.NET
> <snip>
> _______________________________________________
> NANOG mailing list 
> https://lists.nanog.org/archives/list/[email protected]/message/6BU667JNHNF6XEW2G2MAVGZ5G5YCHREA/

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: [email protected]

_______________________________________________
NANOG mailing list 
https://lists.nanog.org/archives/list/[email protected]/message/42IONME5ZXAQWNHGGKXQIWXUXDUGC5W4/