Re: [spfbis] RFC7208 4.6.4 Interpretation - MX Lookup Count Inconsistencies

[[e-mail]]

May be the more relevant question is would these large companies with 
many MXs use "mx" in their SPF record?

;; ANSWER SECTION:
comcast.net.        7200    IN    TXT    "v=spf1 ip4:96.103.146.48/28 
ip4:96.102.19.32/28 ip4:96.102.200.0/28 include:_spfv6.comcast.net 
include:_spf.mdp.comcast.net ~all"

efficient with precise and small ip block space for their mail servers

;; ANSWER SECTION:
yahoo.com.        1137    IN    TXT    
"_globalsign-domain-verification=8DPEanqC-w2Z26VeL5Sn4zBI7cZPCFqrNU5dMKMKeP"
yahoo.com.        1137    IN    TXT    
"google-site-verification=xoBvU6aKxP0gYgNL0iXqF0EccAg6nFrO7XxsHnc3iNQ"
yahoo.com.        1137    IN    TXT    
"google-site-verification=w4N2bNopAWw1xYrdXKORILxx-WW3_LIiyX6dIMIidgk"
yahoo.com.        1137    IN    TXT    
"google-site-verification=Z3-Vh6zqUMgybVH4wQl1GxKSKN7JE13kyCyeZ3TZZ-I"
yahoo.com.        1137    IN    TXT    "v=spf1 
redirect=_spf.mail.yahoo.com"
yahoo.com.        1137    IN    TXT    
"edb3bff2c0d64622a9b2250438277a59"
yahoo.com.        1137    IN    TXT    "Zoom=13284637"
yahoo.com.        1137    IN    TXT    
"facebook-domain-verification=gysqrcd69g0ej34f4jfn0huivkym1p"
yahoo.com.        1137    IN    TXT    
"google-site-verification=2b8irRvU5a2h4Mb-H_fdqNrqWjS00qmPfPcWqm8BhxI"

What a horrific example of TXT record pollution, the door to which was 
opened by SPF ....

;; ANSWER SECTION:
_spf.mail.yahoo.com.    1094    IN    TXT    "v=spf1 ptr:yahoo.com 
ptr:yahoo.net ?all"

On 2023-01-22 19:51, Tim Wicinski wrote:

> I am always happy when I'm proven wrong. Thanks Mr. John.
> 
> tim
> 
> On Sun, Jan 22, 2023 at 10:13 PM John Levine <[e-mail]> wrote:
> 
>> It appears that Tim Wicinski  <[e-mail]> said:
>>> I also feel that technology stacks have matured over time.  Jan, do 
>>> you see
>>> real world examples of a domain with 11 MX servers?
>> 
>> Well, there's Comcast:
>> 
>> $ host -t mx comcast.net [1]
>> comcast.net [1] mail is handled by 50 mx1a1.comcast.net [2].
>> comcast.net [1] mail is handled by 5 mx2.mxge.comcast.net [3].
>> comcast.net [1] mail is handled by 50 mx2a1.comcast.net [4].
>> comcast.net [1] mail is handled by 50 mx1c1.comcast.net [5].
>> comcast.net [1] mail is handled by 5 mx1.mxge.comcast.net [6].
>> comcast.net [1] mail is handled by 50 mx2c1.comcast.net [7].
>> comcast.net [1] mail is handled by 50 mx1h1.comcast.net [8].
>> comcast.net [1] mail is handled by 50 mx2h1.comcast.net [9].
>> 
>> And there's Yahoo, but its MX is only four lookups:
>> 
>> $ host -t mx yahoo.com [10]
>> yahoo.com [10] mail is handled by 1 mta6.am0.yahoodns.net [11].
>> yahoo.com [10] mail is handled by 1 mta7.am0.yahoodns.net [12].
>> yahoo.com [10] mail is handled by 1 mta5.am0.yahoodns.net [13].
>> 
>> $ host mta5.am0.yahoodns.net [13].
>> mta5.am0.yahoodns.net [13] has address 67.195.228.109
>> mta5.am0.yahoodns.net [13] has address 98.136.96.76
>> mta5.am0.yahoodns.net [13] has address 67.195.204.72
>> mta5.am0.yahoodns.net [13] has address 67.195.204.79
>> mta5.am0.yahoodns.net [13] has address 67.195.228.111
>> mta5.am0.yahoodns.net [13] has address 98.136.96.77
>> mta5.am0.yahoodns.net [13] has address 67.195.228.110
>> mta5.am0.yahoodns.net [13] has address 98.136.96.91
>> $ host mta6.am0.yahoodns.net [11].
>> mta6.am0.yahoodns.net [11] has address 67.195.204.74
>> mta6.am0.yahoodns.net [11] has address 98.136.96.76
>> mta6.am0.yahoodns.net [11] has address 67.195.228.110
>> mta6.am0.yahoodns.net [11] has address 67.195.204.79
>> mta6.am0.yahoodns.net [11] has address 67.195.204.77
>> mta6.am0.yahoodns.net [11] has address 67.195.228.111
>> mta6.am0.yahoodns.net [11] has address 67.195.228.94
>> mta6.am0.yahoodns.net [11] has address 98.136.96.77
>> $ host mta7.am0.yahoodns.net [12].
>> mta7.am0.yahoodns.net [12] has address 67.195.204.79
>> mta7.am0.yahoodns.net [12] has address 67.195.204.77
>> mta7.am0.yahoodns.net [12] has address 98.136.96.91
>> mta7.am0.yahoodns.net [12] has address 67.195.228.111
>> mta7.am0.yahoodns.net [12] has address 67.195.228.106
>> mta7.am0.yahoodns.net [12] has address 67.195.228.94
>> mta7.am0.yahoodns.net [12] has address 67.195.204.72
>> mta7.am0.yahoodns.net [12] has address 98.136.96.77
>> 
>> And Charter:
>> 
>> $ host -t mx charter.com [14]
>> charter.com [14] mail is handled by 10 nce.mail.chartercom.com [15].
>> charter.com [14] mail is handled by 10 ncw.mail.chartercom.com [16].
>> 
>> $ host nce.mail.chartercom.com [15].
>> nce.mail.chartercom.com [15] has address 142.136.234.134
>> nce.mail.chartercom.com [15] has address 142.136.234.135
>> nce.mail.chartercom.com [15] has address 142.136.234.136
>> nce.mail.chartercom.com [15] has address 142.136.234.137
>> nce.mail.chartercom.com [15] has address 142.136.234.138
>> nce.mail.chartercom.com [15] has address 142.136.234.139
>> nce.mail.chartercom.com [15] has address 142.136.234.142
>> nce.mail.chartercom.com [15] has address 142.136.234.143
>> nce.mail.chartercom.com [15] has address 142.136.234.144
>> 
>> $ host ncw.mail.chartercom.com [16].
>> ncw.mail.chartercom.com [16] has address 142.136.235.134
>> ncw.mail.chartercom.com [16] has address 142.136.235.135
>> ncw.mail.chartercom.com [16] has address 142.136.235.136
>> ncw.mail.chartercom.com [16] has address 142.136.235.137
>> ncw.mail.chartercom.com [16] has address 142.136.235.138
>> ncw.mail.chartercom.com [16] has address 142.136.235.139
>> ncw.mail.chartercom.com [16] has address 142.136.235.142
>> ncw.mail.chartercom.com [16] has address 142.136.235.143
>> ncw.mail.chartercom.com [16] has address 142.136.235.144
>> 
>> I occasionally see spammy looking hosts with a lot
>> of MX'es but if their SPF checks fail, who cares.
>> 
>> R's,
>> John
> 
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Links:
------
[1] http://comcast.net
[2] http://mx1a1.comcast.net
[3] http://mx2.mxge.comcast.net
[4] http://mx2a1.comcast.net
[5] http://mx1c1.comcast.net
[6] http://mx1.mxge.comcast.net
[7] http://mx2c1.comcast.net
[8] http://mx1h1.comcast.net
[9] http://mx2h1.comcast.net
[10] http://yahoo.com
[11] http://mta6.am0.yahoodns.net
[12] http://mta7.am0.yahoodns.net
[13] http://mta5.am0.yahoodns.net
[14] http://charter.com
[15] http://nce.mail.chartercom.com
[16] http://ncw.mail.chartercom.com