[RndTbl] email-receive blacklist?

Gilbert E. Detillieux gedetil at cs.umanitoba.ca
Thu Apr 29 09:41:07 CDT 2021

Not sure who decided MX records were mandatory, and for what reason. 
There was a time that you supplied MX record(s) if...

1. You needed to specify a different host/domain name for the mail 
exchanger than the particular host/domain itself, or...

2. You had multiple mail exchangers that could handle mail for a 
particular host/domain (possibly with different priorities).

In the simple case of a single host handling its own mail, there was no 
need for an MX record to override the default (the A record was sufficient).

I guess in our increasingly aggressive attempts at fighting spam, we've 
come to treat all the simple, small domains as suspicious?  Or have I 
missed something here?

(And don't get me started on some of the bogus errors that mxtoolbox.com 
reports on perfectly valid SOA serial numbers and TTL values!)

But, ranting aside, thanks to Colin for pointing out the two links, 
which can be quite useful if taken with a grain of salt.


On 2021-04-28 7:51 p.m., Hartmut W Sager wrote:
> Yes, thank you Colin from me too for that link!  As for no MX record at 
> all, really, Trevor??
> Hartmut W Sager - Tel +1-204-339-8331
> On Wed, 28 Apr 2021 at 10:51, Bill Reid <billreid at shaw.ca 
> <mailto:billreid at shaw.ca>> wrote:
>     Thanks Colin for that link. Quite useful.
>     On 2021-04-28 8:46 a.m., Colin Stanners wrote:
>      > It's putting the horse before the cart to look into blocklists
>     etc before the
>      > e-mail domain is correctly configured...
>      >
>      >
>      >
>     http://vger.kernel.org/cgi-bin/mxverify-cgi?DOMAIN=trevor%40tecnopolis.ca&SUBMIT=Submit+to+VGER.KERNEL.ORG
>      >
>     <http://vger.kernel.org/cgi-bin/mxverify-cgi?DOMAIN=trevor%40tecnopolis.ca&SUBMIT=Submit+to+VGER.KERNEL.ORG>

Gilbert E. Detillieux        E-mail:  <gedetil at cs.umanitoba.ca>
Dept. of Computer Science    Web:     http://cs.umanitoba.ca/~gedetil/
University of Manitoba
Winnipeg MB CANADA  R3T 2N2
For best service, contact <cstech at cs.umanitoba.ca>.

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