[Mimedefang] Only MX record is fake

Kevin A. McGrail KMcGrail at PCCC.com
Thu Nov 17 17:39:41 EST 2011

> Those people checking for valid MX records for a sender's domain from 
> within MIMEdefang ... is anybody checking if a sender's one and only 
> MX record is a fake MX tempfailing service? Has anyone ever seen this 
> type of setup for legitimate e-mail?
> For example:
> # nslookup -type=MX babe.org
> Server:
> Address:
> Non-authoritative answer:
> babe.org        mail exchanger = 0 mx.fakemx.net. 
Hi Mike,

I actually plan to add that check to checkvalidMX because it's an 
invalid MX and if it's their only MX (or coupled with other invalid 
MXs), than it's indicative of a spammer IMO.

I spoke to 8086 about that back in May whether that was a problem 
because it's outside of their ToS.  This was his response:

"If a domain lists mx.fakemx.net as it's only MX - mail will never be 
accepted for the domain so I see no real problem with it being 
considered as no valid MX. There is an outside case of someone only 
listing fakemx for a period of time before having a legitimate MX record 
but that isn't what the service is provided for."


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